London, United Kingdom Drinkers raised a glass to the UK's booming brewing scene on Tuesday as the Great British Beer Festival got under way.

The number of British breweries is at its highest for 50 years, with 1,285 now in operation -- 325 of which were serving up their finest ales at the festival, which transforms London's Olympia exhibition hall into the biggest pub in the world.

Real ale has enjoyed a renaissance in Britain over the past five years as more small-scale brewers opened up and urban hipsters latched on to craft brewing.

Some 55,000 drinkers are expected to attend the five-day festival, staged by CAMRA, the Campaign for Real Ale.

The event raises a glass to beer brewed using traditional ingredients and left to mature in the cask from which it is served, as opposed to industrial-scale, pasteurised lager fizzed up with carbon dioxide gas.

- Pressed Rat and Warthog - 

Some 900 different brews were on offer, with beer experts guiding seasoned ale lovers and curious first timers alike through the myriad varieties of styles and flavours.

Some beer names are simply descriptive, such as Chocolate Cherry Mild, Oyster Stout, or Lemongrass and Ginger.

Others stretch the imagination, such as Edith and Mabel, Schrodinger's Cat, Amnesia, Hop a Doodle Doo, Holy Cow, What the Fox's Hat, Skull Splitter, Trembling Rabbit, Dark Side of the Moose, or Pressed Rat and Warthog.

Besides British beers, there were guest tipples from European brewing heavyweights such as Germany, Belgium and the Czech Republic, but also countries including Jamaica, Japan, Iceland and Italy.

Meanwhile ciders and perries -- made from pears -- were also on offer.

Drinkers could choose between a pint glass (568 millilitres), a half-pint glass or a one-third glass, which allows drinkers to sample a wider range of styles without having to swill down a full pint.

Grey-bearded ale fest veterans in faded t-shirts and shorts mingled with younger men in the party spirit, decked out in sombreros and pink flamingo hats.

Punters were trying their skills at old-time pub games including table skittles, roll the barrel and crown top shives: throwing a bottle top through the hole in a beer barrel.

Some drinkers in high spirits even formed impromptu rugby scrums.

Beer-lovers also munched their way through piles of traditional pub snacks, such as pork scratchings, pickled eggs and sausage rolls.

 - Welsh newcomer wins champion beer - 

CAMRA chief executive Tim Page said modern drinkers were more open to trying new beers rather than sticking to the same brew.

"Come and try it. Forget the stereotypes about old, pot-bellied, bearded, sandal-wearing men," he told AFP.

"The bloggerati and the hipsters are interested in new, exciting craft brews and we have a lot of that here.

"Twenty-year-olds rebel against their fathers' tastes, and they were the missing generation attracted to lagers -- so now their children are turning on to real ale.

"The wine industry has been clever and intellectualised wine; perhaps we ought to do that for beer," he added.

"The modern drinker is interested in good beer. We'll show you the difference between what you're drinking now and something even better."

Cwtch, a best bitter-style beer made by the three-year-old Tiny Rebel brewery in Newport, southeast Wales, was crowned the champion beer of Britain. The Welsh word, pronounced "cutch", means "cuddle" in English.

"Cwtch is our modern version of a traditional bitter, with extra hopping for a more pronounced bitterness and aroma," explained the brewery's co-founder Bradley Cummings.

Silver went to Kelburn's Jaguar, a golden ale, with Dancing Duck's Dark Drake stout winning the bronze.