A restaurant that started life as a small family business in a working class neighbourhood in Catalonia, and is still run by three brothers, was has been named the finest place to dine on the planet at the restaurant industry's most prestigious awards.

El Celler de Can Roca, in Catalonia in north-eastern Spain, was voted the world's best restaurant in a poll coordinated by Restaurant magazine, displacing the experimental eatery Noma in Copenhagen, which had held the title for the past three years and was pushed into second.

The winner, which calls itself "a freestyle restaurant committed to the avant garde", was opened by brothers Joan and Josep Roca in 1986, in a plot next to their parents' bar. They were joined by brother Jordi in 1997, two years after their restaurant won its first Michelin star (it now has three). The brothers – Joan is head chef, Jordi head pastry chef and Josep the sommelier – say they learned their passion for food from the aromas of their mother's stews, "generously, simply and honestly prepared", but their cooking has developed beyond simple Catalonian recipes to embrace cutting edge techniques.

Their victory means that Spain's coastal region north of Barcelona has regained its reputation as the world's most exceptional place to eat – the new winner is just 50km from the site of El Bulli, Ferran Adria's legendary eatery which topped the list for four years, but has since closed.

In total, Spain has five restaurants in the top 50, beaten only by the US and France, both of which have six (though the highest placed French restaurant, L'Arpege in Paris, can manage no higher than 16th).

Three British establishments make the rankings, the best-placed of which is Dinner by Heston Blumenthal, based at the Mandarin Oriental hotel in central London, which rose two places to seventh. The Ledbury in Notting Hill, run by Australian chef Brett Graham, also went one place better than last year, at 13th.

But Blumethal's better known restaurant, the Fat Duck in Bray, experienced what might, by its standards, be seen as a slump: named the world's best restaurant in 2005 and runner up to El Bulli for the next four years, it has fallen 20 places in the past year to 33rd place.

Blumenthal was relaxed insisting that the Fat Duck was "in a different league – its 50 to 100% better" than when it held the title: "I said at the time we were number one that you can't really have a number one restaurant, because there are so many great chefs that aren't even in the top 100.

"The awards are looking at where you are in the minute, what's the mood at the time. It's very transient – as it should be. It's not like running a race."

William Drew, editor of Restaurant magazine, said he hoped the ceremony, had broadened diners' awareness of different types of fine cuisine. "They are all very diverse, very different styles of cooking, atmosphere, service style – and price." The best-placed Asian restaurant, Tokyo's Narisawa, was deemed the 20th best in the world, and also awarded the title of most sustainable restaurant, based on food miles, energy, waste and water use and how it treats their staff, as judged by the Sustainable Restaurant Association.

The awards are based on the votes of 900 leading chefs, restaurateurs, food critics and gastronomes from 26 regions around the world.

• This article was amended on 30 April 2013 because El Celler de Can Roca is in Catalonia, not Galicia as the original said.