Never one to shirk a hard day's work, our Clive joins one of the Sussex Wildlife Trust's 'Hit Squads' for a battle with the aliens deep in the Ashdown Forest...

THE tension in the air is almost tangible as I sit waiting nervously in an inconspicuous and unmarked black car. The rendezvous is a couple of hundreds yards down a bumpy track somewhere north of Crowborough. Never having been involved in anything quite like this before, I was anxious not to keep the other members of the 'Hit Squad' waiting and so arrived two minutes ahead of our agreed meeting time of 10.15. Leaning backwards against the headrest while taking care not to be spotted, I can just make out what looks like ordinary woodland. Unless you had been tipped off by Alice Parfitt at HQ, you would never guess that Eridge Rocks is full of aliens. The colourful autumn leaves providing unwitting protection to these most unwelcome visitors. At precisely a quarter past, the rest of the 'Hit Squad' with assorted weaponry packed into the trailer pull off the A26, thunder up the lane and screech to a halt right alongside. It's action stations as we all simultaneously leap out of our respective vehicles and ... have a cup of tea. "We always start with a cup of tea," explains Alice, who has masterminded the whole operation.I'm introduced to the members of the 'Hit Squad' and immediately feel comfortable that I'm among my own kind. In contrast to the enemy lurking in the woods, they are all indisputably British. They are also mature, experienced and thoroughly decent; solid types you can rely upon not to let you down when it really matters. And with a whole day's grappling with aliens ahead, it's reassuring to know that your back is being watched by someone as dependable as these wily veterans of a million forays into the foliage. Forged into a fearsome team by innumerable raids, they now exhibit extraordinary kindness in accepting me - a raw recruit - into their ranks.Formal introductions over and empty cups put carefully back into rucksacks, we set off in search of Himalayan balsam, which is rumoured to be secretly colonising a quiet corner of this delightful nature reserve. The walk provides me with an opportunity to talk to Alice, who works for the Sussex Wildlife Trust and supervises the 'Hit Squad'.Each comprised of a handful of volunteers willing to devote a day a week to help look after the Trust's 32 nature reserves, with three teams respectively responsible for the eastern, central and western sectors of the county. The eastern squad, which I have joined today, meet on Tuesday, the western on Wednesday and the central on Thursday.Mike Mounch, a retired Lloyds Shipping accountant from Ditchling, has been doing his bit for half a dozen years: "I wanted to do something when I stopped working and, having been a sedentary worker all my life, I was looking for a bit more activity." Our first task today is to indulge in a spot of balsam bashing. Himalayan balsam is a relative of the busy Lizzie and is a tall, robust annual producing clusters of purplish-pink, helmet-shaped flowers. These develop into seed pods that open explosively when ripe, shooting their seeds up to 22 feet away. And each plant can produce up to 800 seeds....