It has been known for some time that the chefs at The Ledbury in Notting Hill were probably the toughest in London. Now, it seems, they are the best.

It was only three weeks ago that chefs burst from the kitchen with rolling pins and frying baskets to chase away rioters armed with baseball bats who had crashed through the window and were stealing customers' personal effects. Now the restaurant has been named the finest in the capital by the prestigious Harden's Guide.

The 2012 edition of of Harden's London Restaurants, published yesterday, ranked The Ledbury number one for food. The rating is based on reports from more than 8,000 diners. Its chef, Australian Brett Graham, is only the third cook since 2000 to top the poll. Previous winners were Gordon Ramsay and Marcus Wareing, who took over from his former mentor in 2008.

The Ledbury was awarded its second Michelin star last year after opening in 2005. Mr Graham, 32, said he had never expected such success. "It is a massive honour and privilege to be voted by our customers. That is the most important thing," he said. "I am really chuffed because three years ago we were not even in the top 20. We don't try to get into guides – the best recognition is we are full every day."

The restaurant's tasting menu costs £145 a head with wine. The food is primarily French haute cuisine, with favourites including chestnut and truffle soup and loin of Sika deer, baked in hay with root vegetables, chocolate malt and sauerkraut.

On 8 August, the restaurant's burgeoning reputation enjoyed a significant boost. Chefs and waiters chased a gang of looters away, but barely had they started distributing champagne and whiskey to the traumatised guests than they returned.

Staff were forced to usher the guests into the bathrooms and wine cellar and locked the doors.

Customers at the restaurant on the night praised the staff, calling them "wonderful" and saying they had "gone well beyond the call of duty".

Elsewhere, Clos Maggiore in Covent Garden was voted the capital's most romantic restaurant, while Gordon Ramsay at Claridge's earned the embarrassing accolade for the most disappointing cooking.