Jorge Lorenzo cruised to a comfortable win over defending world champion Casey Stoner in the British MotoGP here on Sunday, with Spaniards also clinching the Moto2 and Moto3 categories.

The Yamaha star, a winner here in 2010 when he went on to claim the title, extended his lead at the top of the championship standings on the strength of this his 42nd career success.

Stoner, who is retiring at the end of the 2012 season, narrowly managed to fend off his Honda teammate Dani Pedrosa for second.

Aside from Lorenzo, who now leads the MotoGP championship by 25 points, the feat of the day belonged to British rider Cal Crutchlow, who crashed heavily in Saturday practice and competed nursing a broken and dislocated left ankle.

Despite his injuries the gutsy Yamaha rider finished an admirable sixth, having left his hospital bed and starting at the back of the grid after missing qualifying.

A drained Crutchlow, an absentee last year after crashing in qualifying, told the BBC: "In all honesty it's been an emotionally draining and tough weekend.

"It was a long day yesterday, they told me at the hospital I wasn't going to be allowed to ride, but the medical staff here did a great job.

"Now I need to make sure I'm fit for the next race."

In dry conditions American Ben Spies, alongside surprise pole sitter Alvaro Bautista on the front row, shot into an early lead.

The Yamaha man was closely tracked by Stoner, with Bautista lying third and Nicky Hayden on a Ducati in fourth.

This quartet were clear of a chasing pack headed by Lorenzo, who turned up at Silverstone having rejected an offer to fill Stoner's place at Honda next season, instead signing a new two year contract with Yamaha.

Stoner, who won by 15sec in the wet here last year, pounced on a mistake by Spies to hit the front on lap five as Lorenzo moved up to fourth.

Lorenzo, perhaps spurred on by having his first taste of a British delicacy - a marmite sandwich - before the race, was up to second by lap seven of 20.

Stoner was being hard pressed by the Spaniard who in turn had acres of daylight between him and Bautista.

At the midway point to this sixth leg of the championship the front pair were treating the Silverstone crowd to a nail-biting battle, with Lorenzo eventually snatching the lead on lap 11.

Having dealt with his Australian rival, Lorenzo surged clear and raced in isolation over the closing laps to register an ultimately effortless victory.

Lorenzo, however, said his win had been harder than it may have appeared.

"I enjoyed it but but there was also a lot of tension. I didn't want to make mistakes to pass and had to wait a little bit to overtake.

"It was wonderful fighting with Casey... We're having a fantastic season, we can't ask for more."

Stoner reflected: "We weren't good in qualifyng, the bike didn't feel right before the race, it was just horrible.

"I struggled during the whole race. I wanted to get in front of Ben (Spies) as soon as possible but knew if they got past it would be difficult to keep up."

Spain completed a clean sweep at Silverstone with Lorenzo's win coming after Pol Espargaro, on a Kalex, had won the Moto2 race and just before Maverick Vinales, riding a FTR Honda, claimed victory in the closing Moto3 event.

AFP, photo-zayitas