Welcome to live coverage of stage four of the Vuelta a Espana - a 160.5km trek through the Pais Vasco mountains which culminates in a Cat.1 climb to the ski station of Valdezcaray.

Valverde was 1:59 down on Clarke, which puts him down to ninth on GC, 36 seconds behind the new red jersey Joaquim Rodriguez.

The Contador-Froome-Rodriguez group crossed the line 1:04 down on Clarke. We're still waiting for a time check on Valverde.

That's a first professional win for Simon Clarke of GreenEdge - and the second time Tony Martin has lost a sprint over a summit finish. The German lost to Juan Manuel Garate on the Ventoux back in the 2009 Tour.

Valverde lost time to his main contenders at the finish so will lose the red jersey tonight. Full confirmation when we get it.

Tony Martin was resigned to take second place, while Assan Bazayev managed to take third. We didn't see him at all on the final climb, but he was clearly still there for Astana. The chasing group comes home about a minute down, with Caja Rural's Marcos Garcia thinking he has won the stage, his arms aloft as he crosses the line.

Simon Clarke goes on the outside and takes it easily! Victory for the Australian and GreenEdge.

It's Martin who is on the front, with Australian Clarke on hsi wheel. Clarke probably has a bigger kick than the time trial specialist. This will be fascinating.

Martin and Clarke enter the final kilometre and they're starting to play around. One of these two will win.

The five chasing riders - Roche, Gerdemann, ten Dam, Zeits and one other - are in pursuit but it's probably too late.

Valverde is not yet back with the group of main favourites as his titanic chase back on continues.

The two leaders have 1:40 over the Roche chasing group, who themselves are 18 seconds ahead of the group of favourites. Euskaltel's Igor Anton is having problems and is off the back. It's Menchov and Moreno driving the pace for Katusha.

Contador and Froome are back with the Rodriguez group. It's very confusing because the Spanish camera crews don't appear to be too clued up on what's happening.

Martin and Clarke still have two minutes over the chasing riders. They have four kilometres to go but it's touch and go.

Roche has pulled clear of Contador, Navarro and Froome and the Irishman rides solo in pursuit of Martin and Clarke. Roche is joined by Gerdemann, ten Dam and Zeits. Contador and Froome must have called a truce and sat up.

Valverde is beginning to look pretty tired now. He made such an effort to get back in the race and will be suffering now. Lucky he has Intxausti with him. Fuirther up the road, Luis Angel Mate has been caught by the Contador group, as has Rosendo.

The Contador quartet have just seven seconds on the Rodriguez chasing group. Roche is setting the pace now, on Saxo Bank work experience so to speak.

It's Simon Clarke setting the pace on the front with Martin. Movistar's Benat Intxausti has dropped back to help out Valverde. Roche is having a super ride alongside his team-mates for next season, Contador and Navarro.

No reaction from Rodriguez as yet as Contador rides with his team-mate Navarro as well as Froome and Roche further up the road. We're waiting for a time check on Martin and Clarke, the leaders. But Valverde is 50 seconds down on the Contador-Froome quartet.

Valverde has reduced the gap to just 20 seconds now. But there's an attack on the front with Froome, Navarro, Roche and Contador pulling clear.

An attack comes from Euskaltel on the front of the main bunch. It's Ivan Velasco, and he finds himself joined by Saxo's Daniel Navarro and Astana's Andrey Zeits.