The Spaniard was unable to convert pole position into maximum points but he at least managed to stretch his advantage in the title race to 26 points from McLaren’s Kimi Raikkonen.

The Finn fought his way through from 12th on the grid, courtesy of a penalty for an engine change, to third by the chequered flag but he still lost ground on his Renault rival.

Raikkonen’s performance helped push Button out of the top three.

The BAR-Honda driver started second on the grid but was unable to remain amongst the leaders, sliding to fifth by the end after Renault’s Giancarlo Fisichella got past in the pits.

World champion Michael Schumacher was handicapped by his poor qualifying effort and he slid further off the title pace with sixth place, one clear of Ferrari team-mate Rubens Barrichello.

Ralf Schumacher netted the final point for Toyota while Scotsman David Coulthard endured a difficult race for Red Bull which earned him a lowly 13th place.

At the start Montoya stunned pole sitter Alonso with a stunning getaway from the second row, passing Button immediately before squeezing past the Renault and into the lead at turn two.

The battle was put on hold briefly though when race officials scrambled the safety car to give marshals time to clear Takuma Sato’s BAR, which had stopped on the way to the grid.

The green flags waved again just a lap later to give Raikkonen the chance to put world champion Schumacher under pressure.

The Finn made a stunning start to reach the top eight in just four laps after starting 12th and he came within a whisker of overtaking Schumacher for seventh a lap later.

Narain Karthikeyan’s adopted home grand prix came to a premature end on lap 11 when his Jordan – which is built just 100 yards away from Silverstone – ground to a halt.

Jarno Trulli’s resolute defence of sixth place frustrated Schumacher and Raikkonen.

With overtaking nearly impossible around Silverstone, the pair of world championship hopefuls were forced to watch Alonso relentlessly pull clear. When the Toyota driver pitted, both Schumacher and Raikkonen immediately lapped over 1.5secs faster.

Alonso’s pit strategy almost got him into the lead after he stopped a lap later than Montoya. But the Spaniard returned to the track side by side with his Colombian rival, who was just able to hang on.

Button lost out in the first round of stops, dropping out of the podium positions when Fisichella crept ahead while further back Raikkonen was able to do the same to Schumacher.

Montoya was able to keep Alonso at bay, quickly reclaiming the time he lost in traffic when the same backmarkers held up the Renault driver.

All the drama was left to the final set of stops, with Fisichella contriving to boost Raikkonen’s chances by stalling his engine.

The Italian’s mistake allowed Raikkonen past into third as Alonso was desperately trying to stretch an adequate advantage over Montoya, who had stopped early.

Alonso slashed the Colombian’s advantage but his efforts proved in vain as he emerged from the pits just behind the McLaren on lap 50.

He pushed hard over the remaining 10 laps but was unable to find a way past the Colombian, who claimed his first win for McLaren, his fifth in total.