A hush descends, interrupted only by the clickety-click of 58 pairs of hands frantically rearranging coloured squares. This is the UK's Rubik's Cube Open Speedcubing Championship. Competitors from around the world are gathered at Bristol's Armada conference centre to show their six-sided puzzle prowess.

The Rubik's Cube is this year celebrating its 30th anniversary. More than 350 million of the puzzles have been sold worldwide and the toy has been experiencing a resurgence thanks to a vogue for Eighties kitsch.

The 58 "cubers", as they like to be known, are keeping their hands nimble ahead of the first round. In front of them a row of four "scramblers" rearrange cubes to an identical (and top secret) unsolved state, generated by computer ahead of the contest.

Among the first competitors to take a seat is Breandan Vallance from Glasgow. The pony-tailed 18-year-old is world and UK speedcubing champion, with an official average fastest time of 9.9 seconds.

Considering there are apparently 43,252,003,274,489,856,000 possible combinations of its coloured squares, it is baffling to imagine how anyone could solve the cube in under a day – let alone 10 seconds.

So what's the secret? "Well, it's pretty easy, you think of it in pieces rather than stickers". So far so simple. "Then there are 57 orientation algorithms and 21 permutation algorithms." This is probably the point at which most people decide it's simpler to take the stickers off and put them back in the right place.

He barely looks at the cube, and his hands blur as if on fast-forward. He secures his place in the final with an average of 10.6 seconds – more than half a second ahead of his opponents. Unlike the world championship title, which earned Mr Vallance €5,000, today's prize is just a trophy, but he's taking it no less seriously.

Like him, most of the contestants are males in their late teens or early twenties, whose skin, hair and clothes suggest they spend a little too much time in their bedrooms. There are exceptions. Charlotte Cooper, 22, one of only three women in the contest, is Europe's best female cuber, with a time of 18.53 seconds.

Ryder Stringer, seven, from Ilfracombe, Devon, is the youngest entrant. He completes it in just over a minute. He has entered alongside his sister Summer, nine, and his brother Louis, 12, who taught himself and his home-schooled siblings four months ago and can complete the puzzle in 22 seconds.

While the "ordinary" speedcubing event may be sewn up by Mr Vallance, a far more difficult challenge is harder to predict. As if solving the cube with your eyes open isn't hard enough, 12 of the contestants are taking it on blindfolded. They are allowed to memorise the cube before putting on an airline eye mask and rearranging it.

Joey Gouly, a 20-year-old computer science student at Manchester University, is the favourite to win, with Britain's fastest blindfolded time of 1 minute 6 seconds. Dropping the puzzle after just over a minute, he throws off his mask and looks triumphant. Then he looks down. The puzzle is still jumbled and his attempt is void. He looks crestfallen: "That was my best chance at a win. There's no point in the main event: no one stands a chance against Breandon."

Mr Gouly's fears are confirmed as Mr Vallance takes the medal with an average speed of 10.4 seconds – almost a second faster than runner-up Rowan Kinneavy, 19, from Aberdeen.

But he has not totally maintained his top position. His UK record for the single fastest solving was broken by Mr Kinneavy, who succeeded in 7.71 seconds in a heat, smashing the world champion's best of 9.28 seconds. "It feels great," he says. "I've done it in five seconds in my bedroom before, but this is different."