LONDON (AP) _ Ken Livingstone began his first full day as London's newly elected mayor Saturday talking by phone to Prime Minister Tony Blair.

Blair, who had warned before Livingstone's election victory that the maverick lawmaker ``would be a disaster,'' phoned Livingstone at Romney House, which is serving as temporary headquarters for the new London government. It was the first time the two men had spoken since Livingstone was declared the winner Friday of the first citywide mayoral race.

They talked for 20 minutes, and their conversation was described by Blair's Labor Party as ``very positive and constructive.'' Livingstone said later that it was ``friendly.''

Livingstone was kicked out of the Labor Party after deciding to run as an independent candidate against the prime minister's preferred choice.

During the often bitter campaign, Blair had warned Londoners not to vote for Livingstone. He said Friday after the votes were tallied that his views had not changed, but that he was determined to cooperate with the new mayor.

Livingstone, dressed casually in jeans for his first day in the office, also promised to work with Blair.

``I'm not worried about what people think about me, but I am worried about what they can do for London,'' said Livingstone, who invited some Labor Party members on Saturday to hold key posts in his administration.

``I don't ask people to love me. I'm not asking them to spend a week on holiday with me. But can we get a bit more money to solve London's problems?''

Blair, who also celebrated his 47th birthday on Saturday, created the mayoral job as part of his program of building up regional government.

As mayor, Livingstone will serve as an ambassador for the capital's 7.25 million residents, oversee a $5.3 billion budget and assume responsibility for the police, transportation, fire and emergency services. He must also work with the newly elected 25-member London Assembly.