For three months a bunch of workmen toiled every Saturday and Sunday morning just across the road from Fire nightclub in Vauxhall.

Clad in the regulation hard hats and high-visibility vests, they had a clear view of happy, messy clubbers stumbling in and out of one of London's best late-night/early-morning venues. Except that that they weren't really workmen.

As punters at Fire suspected last Friday, they were actually undercover policemen who'd been keeping an eye on the comings and goings at the club, culminating in a full-on police raid (Operation Pivot) last weekend.

As someone who has been present at several raided clubs over the years, I can pretty much guess what happened.

The music suddenly stopped, a mass of beefy blokes burst through the doors and started grabbing certain individuals, lots of little plastic bags of drugs suddenly hit the floor in unison and hundreds of innocent clubbers who'd had next to no dealings with the police before found themselves in a scary, bewildering situation.

A similar thing happened at The Fridge in Brixton last April, when 200 police stormed the place and closed it down for a month. Sum total of this very expensive raid? Two drug dealers were jailed. Caught in the crossfire were hundreds of wide-eyed clubbers, who had done nothing more illegal that night than possibly a couple of bad dance moves.

Sometimes the raids are justified, though. Older clubbers may remember the ill-fated, and fairly intimidating, venue that was Club UK in Wandsworth.

With its security run by Essex gangland thug Tony Tucker (shot dead in 1995) and the tragic case of Andreas Bouzis, who died of heart failure there after taking ecstasy, the 400-man police raid there resulted in several arrests and its permanent closure.

To be fair to the police who took part in last weekend's operation, many clubbers commented on the calm and civil nature of their treatment, with one website (gay.com) mentioning the "polite Britishness of it all".

Punters were made to file past a sniffer dog and then had their picture taken by CCTV. This, according to the police, was so that they could photo-match everyone's image against the shots they already had of potential suspects.

After those alarming images earlier this year of South Yorkshire police officers dragging a woman across a nightclub car park by the hair, it's heartening to hear of the Metropolitan Police treating members of the public with notable restraint.

So with south London's best all-nighter shut down until 21 May, where's an early-morning clubber to go? Just around the corner as it happens, with Fire's A:M party moving to Vauxhall's Factory club tonight (11pm-11am) and Sunday (10.30am-8pm).

Otherwise, head west for Jaded's electro house hoedown at The End (Sunday, 6am-1pm). Just keep your eye out for particularly well-groomed workmen with walkie talkies - getting banged up on a bank holiday can ruin your whole weekend.

• clubland@thelondonlite.co.uk