Welcome to coverage of opening practice for thr Monaco Grand Prix.

Join us at 13:00 UK time for second practice from Monaco!

So the world champion tops the opening session of this Monaco GP, as you might expect. The signs ominous for the rest of the field.

Vettel snatches it with 1:16.619! Hamilton does not threaten.

Alonso takes over with 1:16.732!

Hamilton and Vettel forced to back off and use one last lap to top the session.

Vettel goes P1 with 1:16.781 as time runs low...

Button has a problem with his KERS, he is informed on the radio.

Rosberg now leads the way - but Alonso tops it! The new mark 1:17.109.

He leaps the tyres and the W02 is quickly recovered by a crane.

Schumacher into the barriers at Ste. Devote! He was not going fast and is okay, but there is some damage to the Silver Arrow.

Vettel has been in and come back out again quickly, keen to get as much running in as possible.

Hamilton seems set to come back out. He is third behind Massa, also in the pits.

And Vettel has gone top with 1:17.309.

Button, down in seventh now, comes back out. WSR star Ricciardo up to 16th with a 1:20.

Vettel fourth with 1:17.850 while Sutil also improves, to sixth.

F1 champions Red Bull have changed their pitstop procedures for Sunday's showcase after accusing Ferrari of shadowing them at the last race in Spain. /// John: "This will be won in the pits."

Massa the latest 'leader' with 1:17.316 in his Ferrari.

Vettel ominously moves up to seventh with 1:18.868. And Sutil is eighth.

Lewis returns to the pits after 15 timed laps. Alonso also comes in.

Hamilton fastest now with 1:17.350, ahead of Alonso, Massa, Rosberg and Button.