By Alan Baldwin

SILVERSTONE, England (Reuters) - An ecstatic Lewis Hamilton won his home British Grand Prix for the third year in a row on Sunday and his Mercedes team mate Nico Rosberg's overall lead was slashed to a single point.

The triple Formula One world champion, who turned crowd-surfer after the podium celebrations, basked in the adulation of a 130,000-strong crowd as he took the winner's trophy at Silverstone for the fourth time in his career.

The Briton's 47th victory added to his momentum in a championship that Rosberg started off dominating with four wins in a row but has since turned in Hamilton's favor.

"I'm catching him, so let's keep going," he told reporters. "I remember the first time that I got to stand up there with it (the trophy) in 2008 and the feeling today is just as great, if not actually greater."

Rosberg finished as runner-up but, four hours after the race had ended, was handed a 10-second penalty and demoted to third place behind Red Bull's Dutch teenager Max Verstappen for a breach of radio regulations.

Mercedes, who had advised Rosberg to avoid seventh gear because his car's gearbox was failing, said they intended to appeal.

The German had suffered a gearbox problem five laps from the end and crossed the line 6.9 seconds behind Hamilton, with Verstappen a further 1.3 back.

The rules bar teams from giving drivers assistance during the race, except in certain circumstances. The stewards ruled that some of the instructions relayed to Rosberg were permitted but others were not.

In a race that began behind the safety car after heavy rain, before starting properly at the end of the fifth lap, Hamilton led from pole to become the first driver to win three times in a row at Silverstone.

There were a few anxious moments when the slippery surface caught him out but he was never threatened by any of his rivals.

"I don't know if you guys can be as happy as me. I'm really happy," Hamilton told the crowd that stood and cheered him all the way round the final lap with the sun shining at last.

The Briton got even closer to the fans, who flooded on to the track after the finish.

"That wasn't planned," said the Mercedes driver as images of him falling back into the sea of people, smiling serenely with his body supported by raised arms, traveled around the world.

"I could see the crowd there and I just wanted to connect with them in some way."

RADIO RULES

Hamilton is now the closest he has been to Rosberg this season and can take the overall lead in Hungary in two weeks' time.

Red Bull principal Christian Horner said the radio rules were "pretty clear" and questioned where Rosberg, who was booed by some in the crowd as he stepped on to the podium, would have finished had Mercedes not given him their advice.

Rosberg, who had a stirring battle with Verstappen that involved each overtaking the other, said he was confident the team had acted within the rules.

Australian Daniel Ricciardo was fourth for Red Bull, 17.9 seconds behind his team mate, with Ferrari's Kimi Raikkonen fifth.

Mexican Sergio Perez was sixth for Force India, with British-based team principal Vijay Mallya attending a race for the first time this season after India withdrew his passport. His German team mate Nico Hulkenberg seventh.

Spaniard Carlos Sainz was eighth for Toro Rosso and Ferrari's Sebastian Vettel ninth after being handed a five- second penalty for forcing the Williams of Brazilian Felipe Massa off the track.

Sainz's Russian team mate Daniil Kvyat took the final point.

(Editing by Ed Osmond)