London Assembly Member Jenny Jones will tomorrow launch her campaign to become the Green Party's candidate for Mayor in 2012.
Jones who is a regular combatant of Boris Johnson on the Assembly was the former Deputy Mayor of London between 2003 and 2004.
She describes herself as a "critical friend" of the former Mayor Ken Livingstone, but has not announced whether she would recommend second preference votes for the Labour candidate.
She said today:
"London needs desperately the green measures that a Green Mayor would introduce for a cleaner, safer city. Whether it's cleaning up on air pollution, investing in public transport, increasing the supply of affordable homes, or keeping the police local, Greens deliver on their promises and work for the whole of London."
Her fellow Green Party Assembly Member Darren Johnson will stand as her running mate. No other candidates have yet to declare their intention to stand for the party.
If selected, Jenny Jones would become the third declared candidate for 2012 with the Liberal Democrats the only major party yet to choose a candidate.
Selection for the Liberal Democrat contender was recently delayed after only Lembit Opik got through the initial selection process.