COCKTAILS used to be what ladies in strappy dresses with cigarettes poised in holders drank in pre-war films, while the cocktail piano tinkled in the background.

Now they have abandoned their air of upper-crust sophistication and have reappeared as the drink for fun-loving trendies.

They used to be considered as not very British, says Mat Miller: "Cocktails are big in America and Australia. In Britain I suppose we've always been into little pubs and pints and ale.

"But with people travelling a lot, and with some of the big hotels employing American bartenders, cocktails are big news again.

"People love the fun element. And they're the ideal drink when you want something special, like at a garden party or a wedding, but don't want power drinks. A cocktail isn't about drinking to get drunk."

Mat has just set up in business in Downley with his brother-in-law Justin Modray to set up Mimosa, a mobile cocktail bar, which they believe is the first in its field.

They have designed a mobile bar and canopy that can be set up in a garden, park or even car park to provide drinks and cocktails for events and parties ranging from 20 to 250 guests or more.

Mat says: "One of the biggest challenges that we initially faced was designing a full-sized cocktail bar that would collapse into a trailer for transport. I'd never thought that my design degree would prove so useful."

He and Justin gave up their jobs Mat as a sales manager, Justin in financial PR to set up Mimosa and take the bar to events throughout the south-east.

When they set it up on the Bucks Free Press lawn this week, I found I had a lot to learn. Mat's the whizz-kid at flairing the art of doing tricks, throwing bottles and twirling cocktail shakers while serving. You can even go in for championships. He brought along Iain Stacey, from Thame, who was UK tandem bar champion 1999 and who fascinated us with his tricks.

Mat learnt the skill from the world bartender champions and worked for a while at TGI Friday's when he left university, and then went on to teach others.

The crucial thing about making up a cocktail, not surprisingly, is to get the amounts right. Cocktail bartenders don't use 25ml shots as in pubs, they uses ounces and must learn how to pour, using time as a gauge. Long Island ice tea, for instance, takes oz each of vodka, gin, rum, triple sec and sweet & sour topped with coke. All you need to remember is that an ounce takes one second to pour. Right?

There are more than 400 cocktails in the compendium, all based on the common definitions of worldwide favourites like woo woo and sunset boulevard. But Mat and Justin can devise you a drinks menu for a specific event. A recent Bar Mitzvah party had a Bond night theme, and they produced cocktails all named after 007. Another set of cocktails was devised to fit in with a casino evening on a Hollywood theme.

"It's all about being individual and original," Justin says.

Since lunchtime boozing is frowned on by our bosses, we tried some of Mimosa's non-alcoholic cocktails. They looked delightful, they tasted wonderful.

And I learnt another thing: a good bartender doesn't pack a pile of ice into the glass so he can cut down on the drink. Nor will it dilute the drink. The more ice, the more quickly the drink and glass get cold and less quickly the ice will melt into your drink.

November Seabreeze was a winner: cranberry juice, apple juice and sweetened lime juice topped with soda.

Virgin pina colada Mat's home made pina colada mix blended with ice was judged terrific, with so much flavour testers said they didn't miss the alcohol. It's made with pineapple, orange, lime mix, papaya juice, cream of coconut and fresh pineapple. Then it's blended with ice to the right consistency. And how do you know it's right? "When you push a straw in one and a half inches, it should stand upright," Mat says.

Mimosa mobile cocktail bar 01494 436066 or 07900 271402

Special offer to Bucks Free Press readers

Mimosa mobile cocktail bar is offering Bucks Free Press readers a special offer for events held before the end of July.The set-up fee of £250 will be waived, with the customer paying only for drinks consumed, minimum party 30 people.