What larks:

London mayor Ken Livingstone has dismissed claims that some Labour supporters are trying to block Boris Johnson’s bid to stand against him.

The Tories are holding open primaries allowing all Londoners to help choose the party’s candidate.

Two websites are urging Labour voters to take part, leading to claims they might choose a weaker candidate.

Still, the Tories should look on the bright side, Labour activists are doing their fundraising for them:

Any London voter can take part in the Tory primaries, which are intended to boost interest in the contest, but they have to call a £1.50 premium rate phone line in order to register.

With a following wind, these berks should put quite a few quid in the Tory coffers. The more people Labour astroturfers get to participate, the richer the Tories get.