LABOUR top dogs are jockeying to become the natural candidate for London mayor — in the wake of Boris Johnson’s announcement that he has greater ambitions.

The party will not fire the starting gun for its mayoral selection until after next year’s general election. But likely candidates toured TV studios yesterday to opine on the capital’s future.

Labour London spokesman Sadiq Khan and Blairite former cabinet ministers Dame Tessa Jowell and Lord Adonis are media favourites.

But opinion polls say no candidate has a solid support base. The most recent survey saw Ms Jowell ahead with 12 per cent support among Labour voters, trailed by Diane Abbott on 8 per cent and campaigner and Labour peer Doreen Lawrence on 7 per cent.

Mr Khan and Lord Adonis each commanded just 6 per cent.

The only declared candidate is campaigner and transport journalist Christian Wolmar. Tottenham MP David Lammy also intends to stand.

The “selectorate” voting on the party’s candidate will be made up of party members, trade unionists who have “opted in” and registered supporters who will pay a small fee to take part.

One party insider said that the field of candidates may narrow as the selection approaches.

A source close to the selection warned that criticisms of Ed Miliband may affect the outcome.

But another party figure said Lord Adonis may withdraw in favour of Dame Tessa as an “establishment right-wing candidate.”

They said Ms Abbott is likely to gain the support of at least one major union.

“She has a media profile and a lot of recognition in the black community,” they told the Morning Star. 

“She’d be a real recruiter of registered supporters — I don’t think any of the others would find that easy.”

Mr Khan has been accused of arrogance for no-shows at informal hustings.

Mr Wolmar said it was a mistake for the party to delay the selection until next summer. 

“We could have started it immediately after the election and got it done by September,” he said.

“Then we’d have a figurehead for London in the general election. The Scottish referendum has shown that having a big debate in public is good for politics generally.”