While I'd undertaken plenty of research into the work of ASU prior to the visit I'd not done any investigation into the Lippitts Hill site itself, but as soon as we'd cleared security and parked up it became very apparent that this was an interesting location in its own right.
The buildings were almost exclusively single-storey, wooden structures, the type of which you'd have expected to see in films portraying the Second World War.
That theory was soon confirmed when we were met by Tony Donnelly, our host for the day. Tony explained that the base's position on a hill rising above the Lee Valley provided an excellent vantage point from which to see approaching enemy bombers using the reservoir system to navigate their way in for bombing raids against London.
ZE7, as it was known, was one of Britain's premier heavy anti-aircraft gun sites during World War II. Becoming operational in January 1940, the battery was equipped with 3.7-inch guns and by 1943 was operated by a mix of both men and women. At the end of that year the site was handed over to American forces with the 184th Anti-Aircraft Artillery firing the first US guns in defence of London in March of the following year.
The Americans were not resident for long however and had once again been replaced by the British by the end of 1944, but, with very little for them to defend against, the base saw out the conclusion of hostilities as a Prisoner of War camp.
An impressive statue carved by prisoner Rudi Webber in 1946 still rests on the grass near the entrance today, while many of the buildings on the camp were given Listed Grade II status in 2003, and the 'Spider Block' is believed to be an extremely rare example of wartime shared accomodation.
After an extended period of care and maintenance the local civilian police began using the site. A firearms school was setup there and later Lippitts Hill became the base for all armed police. Helicopters have been in residence since 1967 operating under various guises.
The Metropolitan Police Air Support Unit was formally activated in 1980 with Bell 222A helicopters, and, in 1993 a joint initiative with Surrey Constabulary commenced. The same year saw the transition to the AS.355N Squirrel helicopter begin, often operating from a landing site initially at Redhill and, from September 1994, at Fairoaks, Surrey. In April 1996 the unit was renamed the South East Regional Police Air Support Unit, and that's how it was known until the two Forces once again went their separate ways in 2001.
The three Eurocopter EC145s that the ASU operates today were delivered in July 2007 to replace the Squirrels at a fully-fitted cost of around £5m per airframe. They each cost approximately £1500 per hour to operate, but their value to the Force is literally immeasurable, and in those 30 or so months each helicopter has accumulated just over 2,800 flying hours.
Obviously their operation has to be funded from somewhere, but given the nature of the job they're expected to undertake, how can you budget for something that's almost impossible to predict required usage levels?
Tony explains, "Between the three aircraft we're allocated 3,300 operating hours per year, but, like everything else, that figure's continually under-review, and there are increasing pressures for our allocation to be reduced.
"It does mean we need to prioritise over what jobs we do and don't take. Some requests, such as pursuits, we have to do, but someone suspected of stealing goods worth a nominal value from a shop isn't something we would necessarily assist with. That said, safety of the forces on the ground is paramount and if circumstances dictated that it was safer for them if we were present then we would attend. Rooftops, railways, water and garden searches are all trigger factors that would lead to us turning out."
The ASU is often deployed in a counter terrorism role, regularly monitoring a number of key points throughout London; to act as an escort, both for VIP and high-risk prisoner movements; in a crime reduction capacity, by maintaining a visible presence; in the tracking of stolen vehicles; to maintain public order, at events like Notting Hill Carnival, demonstrations, marches and some football matches; and additionally in the transportation of police specialists.
As well as routine taskings the Unit is also on a continual state of rapid alert standby, 24 hours a day, 365 days a year. It might be to assist with a search, either for a suspect or a missing person; a vehicle pursuit; or to provide an aerial view of any firearms incidents. It's possible for them to be airborne within two minutes of the siren sounding, and their location, just inside the M25, puts them in an ideal position that Tony proudly states enables them to get anywhere within the M25 in 12 minutes.
For a typical day where no major taskings are planned one aircraft will be the preferred 'cab', there'll be a backup airframe and the third will be undergoing scheduled maintenance.
Each aircraft has a typical crew of three; one pilot and two police officer observers, who between them operate the incredible equipment strapped on to each helicopter.
The ASU has 11 pilots and 18 officers on strength, and each member of the team will work a four-on, four-off shift pattern, with each shift lasting a full 12 hours - either 0700-1900/1900-0700 or 0800-2000/2000-0800. With two pilots on station at all times, the hour offset in start/finish times means that there's always cover near shift changeovers. For the pilots the four-on will all either be days or nights, and for the officers the first two will be days and the second two nights.
While drinking a cup of coffee in the crewroom we were joined by Capt Neil Goodenough and PC Steve Chard. Neil reminds Tony that he needs to get Geoff and I weighed. It seemed we were going flying with them!
With coffee still in hand Tony led the way out to the ramp to acquaint us with the EC145, the assorted paraphernalia bolted on to the front end of the aircraft and the safety procedures in the unlikely event that the worst should happen.
The ball turret on the starboard side of the nose contains both a video camera and a thermal image sensor. The video camera has two different lenses which can be used. The first is a zoom with magnification between 10 and 200X, while the second is fixed at 1000X zoom. Tony says that you can pick out a car registration from two miles away with the latter, though we're assured that this type of technology is not used to catch speeding motorists!
What can be achieved with the use of this technology is quite staggering. If the ASU receives a 'shout' to attend a burglary, for instance, simply inputting the address into the computer is all that is required to get the camera to point at and maintain a fixed lock on that location from the very moment they get airborne. The closer they get to the location the more focussed the pictures become.
The thermal image sensor is exactly as you would expect. It scans to an accuracy of 0.1 of a degree and converts the information into a visible picture. As one might assume this really comes into its own in the dark, but the priciple is equally effective in the daytime. We're told that it's so powerful that you can even pick out rats with it!
On the port side skid is the 'Nitesun' searchlight, capable of lighting up an area the size of a football pitch or pinpointing a single suspect in the darkness with its phenomenal 30 million candlepower rating. It can be directed by either the pilot or the rear observer.
In addition to being able to record what's being seen with the onboard equipment, the EC145 is also fitted with a retractable aerial on the left hand skid that enables real time images to be transmitted to, amongst others, Central Communications Control (CCC). Much like in a warzone - it's essentially the same technology - this can be of huge value to both those directing operations and the actual officers on the ground.
The radio system carried is equally impressive in its own right. The aircraft has a comprehensive radio suite enabling the crew to monitor and talk to units on a whole host of channels. They can communicate on all Metropolitan Police Service main channels, local borough radios, the main emergency channel of every police force in England and Wales and also the channel used by firearms officers and the London Fire Brigade.
The aircraft also has two radio boxes for Air Traffic Control frequencies, which are constantly monitored by the pilot and observers. What that means is that up to six different radio channels can be monitored at any one time. Each channel can be selectively blocked out and the volume for each tuned up or down accordingly.
Our familiarisation complete, it was time for the day's spare aircraft to be air-tested following some minor rectification work. There was plenty of snow lying on the ramp and surrounding area and we hoped it might produce some spectacular take-off images, but most of the snow was a bit too crunchy and solid.
Geoff had been humming and harring about whether he even wanted to fly, but, armed with not one but two 'sick bags' he somewhat reluctantly decided he had to go for it. We strapped ourselves in as the crew went through their pre-flight checks and were given a rough 'plan of action'.
Our first tasking was to head north towards Watford to see if we could track-down a stolen digger. After that we'd be heading to Heathrow Airport to perform one of the regular security checks that the ASU are tasked with carrying out. This one in particular made both Geoff and I perk up!
As neither of those tasks were desperately time sensitive there was the possibility that we might be called away to attend to all manner of incidents along the way, but Tony told us that in general daytimes are quite quiet. The night is when it really comes alive with half of a twelve hour shift typically spent in the air.
Checks complete, Neil, our pilot, called for clearance to start. Our ATC callsign was 'Police 251' while our tactical one was 'India 99'.
As is normal with rotary operations, the aircraft captain sits in the right hand seat. Observer 1, in this case Tony, was in the left hand seat, while Steve was Observer 2 in the work station behind Neil. I was then sat behind Steve, with Geoff in the left hand corner of the three-man backseat.
The EC145 is, even with all the gear in it and five blokes, a surprisingly spacious helicopter - even before taking the space aft of the rear seats into consideration.
The ASU are currently waiting for a recently laid down runway to receive CAA clearance for use, so for now, departures are flown to what Tony referred to as VTOL1 - that is up and back from the tarmac hard-standing. The theory is that if you suffer a double engine failure in the climb (the EC145 has two) you have enough energy to auto-rotate down on to a surface that you know for certain to be sound.
So, with the engines fully spooled up we climbed a handful of feet above the ground, span round through 90 degrees and began our VTOL1 departure, with Neil pointing the nose down slightly at the top. All was good, and the sight of acres upon acres untouched snow provided an extremely picturesque backdrop as we headed towards Watford, passing the de Havilland Aircraft Heritage Centre that I'd seen when flying into London-City Airport's Fun Day in July with the Swift Aerobatic Display Team, along the way.
Without any success on the digger-hunting front we routed to Heathrow via a very snowy (and closed!) Elstree Aerodrome, through RAF Northolt's overhead and then on to the H9 London Heli-route, as we tracked south.
It was during this part of the journey that the power of the on-board cameras really began to hit home. Firstly as we'd tracked across Northolt Tony locked on to a Royal Netherlands Air Force Fokker F50 that was sitting on the ramp. Clear as day, the name "Robbie Wijting" could be read off its nose! A matter of seconds later and someone pointed out the Qantas A380 that had just taken off from Heathrow. Sure enough it magically appeared on Steve's monitor in thermal imaging mode, engines giving off heat and efflux pouring out of the back of the exhausts.
And before we knew it, Neil called the tower at Heathrow and sought permission for us to carry out security checks of both the north and south sides of the airport. With the prevalent wind from the east, runway 09 was in use; left for arrivals and right for departures.
I was, sadly, on the 'wrong' side of the helicopter for the northside checks, where we were essentially looking for any suspicious activity, while at the same time providing a visible presence to anyone on the ground.
Geoff's view as we approached and then crossed the threshold at the active departure end was rather special. As 'T5' started to disappear into the distance the spectacular sight of aircraft lined up waiting to depart took its place.
It seemed utterly bizarre that take-offs and landings were taking place all around us. I'm sure the sight would have been all the more impressive had the weather, which by now was starting to close in a little, cooperated more, and it might even have been possible to achieve some passable shots of departing aircraft.
As we approached the 27L threshold we turned and flew back west, finally giving me an opportunity to properly savour some of the sights for myself. One of the first things to come into view was Terminal 4, where, amongst others, a Continental Airlines 777 was being de-iced on its stand.
The Cargo Centre, which we'd heard a lot about during our recent visit to DHL's East Midlands Airport operation soon followed, and, sitting beyond that, was that line of aircraft preparing to depart once more. The Thai 747-400's waiting was over though, and as we once again approached T5 it started its take-off roll, kicking up plenty of spray as it did so - a truly memorable sight.
Tasking at Heathrow complete, our routing now took us down over Hampton Court, just to the south of Centre Court at Wimbledon, and then on towards the River Thames, Battersea, Buckingham Palace, Westminster, Canary Wharf and so on. There can be few better ways of seeing London's sights!
Following a string of burglaries in the Hackney area the ASU had been asked to provide an aerial presence to serve as a reminder to the perpetrators of just what they might find themselves up against 'next time'. A more civilised kind of 'Show of Force', I suppose.
While on station there we received a call on one of the tactical frequencies asking for our assistance. A van used for the secure transfer of money had been held-up, with those responsible making off with an undisclosed amount of cash. One man had been captured by officers on the ground. It was alleged that he'd already disposed of the bulk of the haul prior to his arrest, so we were called in to hunt for what was described to us as a 'large blue bag' between two specific locations along the side of the railway line.
Neil put us into a hover while Steve and Tony used the camera equipment to pan up and down the track, zooming in on anything vaguely matching with the description of our target item. Between them they did come up with one possible match and directed officers to it.
As Steve pointed out, it's of huge benefit to be able to do this sort of task with a helicopter. Not only can you perform a search of a large area in a very short space of time, it also means you're not deploying a potentially large number of officers on wild goose chases and in potentially dangerous situations - such as alongside railway tracks.
With our fuel beginning to run low we departed the scene before we could learn the outcome of whether our match was a positive one or not. Our route back to Lippitts Hill took us past the main site for the 2012 Olympics at Stratford, Leyton Orient's ground and the now defunct greyhound racing track at Walthamstow.
During the short transit back I asked Neil about his background and was told that he was ex-Royal Navy, initially on the ASW (Anti-Submarine Warfare) version of the Sea King and later on its Search and Rescue (SAR) counterpart. After coming out of the military he then joined the Chiltern Air Support Unit, flying their Squirrel helicopter from Luton Airport, before making the transfer to the Met's equivalent.
How does Police flying compare with its military counterpart? Presumably the uncertainty about what you're likely to encounter on any given day must allow some parallels to be drawn?
"Very much so. It's that part of the job that keeps it interesting. You just never know what tasking you're going to get next. There are differences though, and I guess the biggest is that with the ASU we're overseen by the CAA (Civil Aviation Authority), whereas in the military we weren't.
"The Police Air Operators Certificate (PAOC) on which we operate clears us down to 300ft in daylight and 500ft at night and, most crucially, over built-up areas."
Soon enough our final destination came back into view. Neil flew us down the runway, displacing a disappointingly small amount of snow, as he prepared to put us back down on the spot from which we'd departed. It was very nearly one of those landings where you needed to be told that you were down, such was the smoothness of the contact.
Geoff and I both looked at one another, each of us more than a tad disappointed that our experience had come to an end, and, slightly surprisingly, Geoff's sick bags still remained in their unused state!
Back in the crewroom with a fresh mug of coffee in hand, I asked Tony if Neil's background made him a 'typical' ASU pilot.
"Absolutely. All of our pilots have similar histories. I think it's safe to say that we, as an organisation, have recognised the value of having ex-military people on the team. They're supremely well trained, highly capable and do exactly the job we require."
Just from the short time we'd spent with the unit it was obvious that this was a really fascinating aspect of the Metropolitan Police Force, and it seemed reasonable to assume that a position on the team would be something that large numbers of PCs would aspire to.
"I was the last person to come here and from memory there were something like 40 applicants in total for this single position, and to be honest, I think a lot of other people would've been put off from applying simply because the chances of getting it were so slim," Tony says.
Perhaps the best way to measure the success, or otherwise, of the police's use of helicopters up and down the country is to consider the attacks that a number of them have been subjected to over the last few months. On the last day of April 2009, Surrey Police's EC135 was immobilised for several days after its windows were smashed with an axe as it sat on the ramp at its then Fairoaks base. In the most serious of the three attacks of the year, the West Midlands Police Force helicopter was gutted after being fire-bombed within the perimeter of Birmingham's International Airport. And finally, in October, the Merseyside Police helicopter was disabled following an arson attack at its RAF Woodvale base.
Security measures have naturally been stepped up across the country since, and several forces have actually relocated their helicopters to what are perceived to be more secure locations.
That criminals are prepared to go to such extreme measures to disable these unbelievably powerful pieces of equipment tells you all you need to know about the value of these assets in the policing of the UK. And when you consider that an area of land that would take 450 man-hours to search can be covered by a helicopter in just 12 minutes, or its ability to pursue vehicles through both agility and its top speed of 167mph, it's not hard to see why.
Tony added: "We had a tasking quite recently where we received information that someone wanted for murder was out playing a round of golf. We launched, loitered a couple of miles away, confirmed it was him and then directed officers on the ground into position out of view. Then, as he got to where they were waiting, they jumped him and successfully carried out his arrest."
He also admitted that they do get their fair share of noise complaints, both from their immediate neighbours and also in areas in which they're tasked.
"There was one instance where we had a lady ring up to complain about the noise we were generating. We got her to confirm her address and it turned out that she actually lived next door to a location we were attending where a burglary was on-going.
"The noise didn't seem to be so much of an issue once she was aware of this fact!
"We are conscious that we do make quite a lot of noise, however, and over the course of the year we'll try to attend as many events as our hours will allow to get out there to meet the public, to try to educate them on what we're doing, why we're doing it, and to hopefully make them a little more tolerant during the times where we are disturbing their peace."
Geoff and I had been at the ASU for about four hours, and while it didn't feel as if we'd really experienced the EC145 in full flow, we'd definitely seen enough to appreciate just what it and the staff at Lippitts Hill are capable of - the deterrent threat alone must be massive.
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