Ken Livingstone is to choose a new deputy mayor of London to replace Labour's Nicky Gavron.

The mayor confirmed the move on Wednesday, amid speculation that Green Party assembly member Jenny Jones could become his new deputy.

With reports suggesting her dismissal will take effect on July 3, the Labour assembly member reacted angrily to the move.

She told the Evening Standard newspaper it demonstrated the mayor's "poor judgement".

Gavron said that Livingstone was attempting to court the Green vote even though the party had opposed many of his key policies.

"He is putting his campaign above the interests of Londoners," she said.

But Livingstone said that he was honouring a pledge to rotate the deputy mayor position.

"I gave a firm and public commitment in the mayoral election to rotate the deputy mayor position. I am simply implementing my pledge," he said.

"Nicky Gavron has been an excellent deputy mayor and I look forward to working with her in the future on our common agenda for London."

Gavron was appointed deputy mayor after Livingstone won the top job in 2000.

The two have worked closely for the past three years.

But Livingstone may calculate that with the capital's voters growing disillusioned with Labour after the Iraq war and the Greens polling strongly in other parts of the country on May 1, the time has come to strike an alliance with a smaller party.

The offer to work with Gavron was seen as an olive branch to Labour following Livingstone's fractious exit from the party after it failed to select him as its candidate.

The partnership was initially meant to be for just a one year term but Gavron was then kept on.

She successfully won the Labour candidacy this time around on a ticket sympathetic to Livingstone.

Some saw her stance as implying a move not to campaign aggressively against the incumbent.

But Livingstone may now consider her a sufficient threat to his job - along with high profile Tory Steve Norris and Liberal Democrat Simon Hughes - that he needs to put "clear red water" between them.

The election for City Hall office involves a second preference, alternative vote ballot.

Voters are invited to make first and second choices for the job, allowing candidates to recommend who their supporters rank behind them in the event that they are eliminated from the ballot.

With the Greens tipped to put in a strong showing in 2004, Livingstone may see the second preference votes of their candidate, Darren Johnson, as crucial to his chances of success.

And working with Jones could help to build the alliance.

Her biography states that she marched with CND as a student in 1968 and worked as a volunteer with Shelter.

She joined the Greens in 1988 and became chair of the party's national executive from 1995 to 1997.

As a mature student she qualified as an archaeologist and for many years worked in the Middle East. Before her election she was working in London as a financial controller.