Tis the season to be merry. Just to make sure, you could do what one London student did recently and knock back 28 tequilas in a night.

According to the Slammers, a group of posh girls who serve tequila slammers from low-slung leather holsters at parties, he was probably just enjoying the company. 'It's all part of loosening up,' says Julia Fullerton-Batten, loading up her twin bandoliers with shot glasses.

In a back room of a double-glazed, hard-floor marquee in Battersea, the girls were strapping on the pounds 500 belts - made of hand-tooled leather from Mexico - over their stretchy black outfits, preparing to face a bankers' Christmas party.

Slammers offers a stable of willowy, well-bred young women, pounds 250 for two (although tonight there are five). The girls pour a mixture of Jose Cuervo tequila (the Silver variety, which is cheaper than the Gold) and ginger ale, fizz it up (to precipitate intoxication), and, should he or she dawdle, pour it down the party-goer's throat. Not without charm, of course; and in this situation they need every ounce of it.

At 9.30pm the tent holds a youngish crowd, dressed to match the Wild West theme. Three secretaries enter as a pantomime Roy Rogers and Trigger. About five people clap. Compared with the horse, the Slammers girls get a warm welcome when they hit the floor and begin working the tables, cajoling the fainthearts and blowing whistles as each drink is downed. The women, said one Slammer, enjoy themselves just as much as the blokes.

Within minutes fresh supplies are needed, and after half an hour Vanessa Birrell, 23, sits down on a papier mache rock for a breather. She is a secretary by day, but appreciates the pounds 60 she earns and likes working with her friends. 'There's something about having the bottles on each hip that feels powerful. It's like 'Here's what you want, and I don't have to give it to you.' And you don't have to be nice like a waitress. You can tell them to get lost if they get out of hand.'

By 11.30 they have gone through the first case of tequila. Cathy Fullerton, Julia's sister and a model, reloads, tosses back her white cowboy hat, and dances athletically to a Madonna song. 'I get a buzz seeing them get drunk,' she says. 'I see myself as an entertainer. The other day I was dancing with this tiny fellow, two heads shorter than me, but we had a great time. All his friends cheered us on.'

All five Slammers hang out together for a quick break, then the sisters cross the room to the dance floor, their swagger enhanced by the full holsters. Several guys in zany waistcoats swarm round them for some dirty dancing and a top-up. The other three do the rounds again, by now dispensing as many neat shots as mixed drinks.

The bandoliers crossed on their chest remind one of Rambo posters. 'The guys tend not to grab you with all this stuff hanging off you,' says another of the girls, an actress practically still damp from playing Ophelia in fringe theatre who doesn't want her agent to know about her job on the side.

They're clearly having more fun than some of the party guests, who by midnight are down to a hard core of a hundred in the huge tent. The bank has to open for business the next day.

At 12.30am, however, Cathy Fullerton and another girl discover that their wallets have been nicked from their bags. 'Oh no] My Access, my Visa] Miss Selfridge, Harvey Nichols . . . bastards]' This must be what they call corporate raiding, someone says.

Suddenly feeling short of fizz, the girls decide to call it a night. They pack up their gear and go, leaving full bottles of tequila still lying around and the bank staff stumbling round happily in their wake.

Slammers can be reached on 081-878 0800.

(Photograph omitted)