Livingstone's speech to deliver a coup for Greens

Ken Livingstone, the Mayor of London, is to take advantage of his freedom from party politics by addressing this year's Green conference.

The left-wing former MP expelled last year by Labour for standing as an independent in the mayoral election, will be the star attraction at next month's conference in Salisbury.

He is expected to use his address – on his work with the Greens in the Greater London Assembly – to deliver a wide-ranging attack on Labour moves to attract more private money into public services. Mr Livingstone lost his court battle this month to block the Government's Public Private Partnership plans to revive the London Underground.

A Green spokesman said that Mr Livingstone's appearance would be the first time a senior figure from another party had spoken at one of its conferences.

He said: "Our three representatives on the GLA are active members and have very close dealings with him. It's often been the case that the Mayor has been closer to the Green Party than to the other parties in the policies he is promoting."

After Mr Livingstone was cold-shouldered by Labour, he forged links with the Greens, appointing Darren Johnson his environmental adviser. But signs of strain have emerged in recent weeks, with Mr Johnson, a GLA member, accusing the Mayor of "sitting on his hands" on the environment.

Mr Livingstone will attempt to rebuild bridges with the Greens in his Friday afternoon speaking slot, guaranteed to win coverage for a conference usually ignored by the press.

The publicity will be a welcome boost for a party that struggles to remain in the media spotlight despite its recent successes in London, Scottish and European elections.