Conservative conference: Boris Johnson tribute to PM 'Dave'

London Mayor Boris Johnson has paid tribute to Prime Minister David Cameron, praising his "firm leadership" and ability to take "tough decisions".

Mr Johnson began his speech by gazing out into the audience and saying: "Where is Dave?"

Having spotted the prime minister, the London mayor wished him a happy birthday and backed his strategy to "turn the country round".

Mr Johnson has had a hero's welcome from Tory activists in Birmingham.

But he has denied trying to upstage the PM, who gives his big speech on Wednesday.

'Can-do country'

Mr Johnson, who who is riding high after the London Olympics and his re-election, said Britain had a "chronic tendency to underestimate what we can do".

The London games, he added, showed "we are a can-do country, a creative, confident can-do country".

In an upbeat speech - packed with jokes and digressions - he talked up what he sees as his main achievements as mayor and paid tribute to some of the politicians, including Sir John Major and Labour figures such as Tony Blair and Ken Livingstone, who had contributed to making the Olympics a success.

He joked that his defeated rival for the mayoralty, Mr Livingstone, was now well and truly "finished" after receiving a round of applause at a Tory conference.

David Cameron laughs and points during Boris Johnson's speech

He joked that Mr Cameron had called him a "blond-haired mop" in the Daily Telegraph, adding: "If I'm a mop then you are a broom, a broom that is cleaning up the mess left by the Labour government and a fantastic job you are doing.

"And I thank you and I congratulate you and your colleagues George Osborne, the dustpan, Michael Gove, the jey cloth, William Hague, the sponge.

"Because it is the historic function of Conservative governments over the last hundred years to be the household implements, so effective on the floor of the house to clear things up after the Labour binge has got out of control."

Mr Cameron laughed along with Mr Johnson, the man seen as a potential future leadership rival, even when the mayor, a classical scholar, ribbed him about claiming to not know the meaning of Magna Carta.

'Age of enterprise'

The mayor ended his speech with a rallying cry to Tory activists, who gave him a standing ovation.

He said: "We fought to keep London from lurching back into the grip of a Marxist cabal of taxpayer-funded chateauneuf du pape-swilling tax minimisers and bendy bus fetishist.

"I will fight to keep this country from lurching back into the grip of the two Eds, Miliband and Balls. Unreformed, unpunished, unrepentant about what they did to the economy and the deficit they racked up.

"We need to go forward now from the age of excess under Labour.

"Through the age of austerity to a new age of enterprise in which we do what we did in the Olympics and build a world-beating platform for Britain for British people and businesses to compete."

'Comedian'

Mr Johnson later told the BBC Radio 4's World At One programme he would welcome the "spotlight" moving on from talk about his future plans, speculation which he described as "tired and hackneyed".

Asked about the furore surrounding Mr Johnson at the conference, Tory donor and strategist Lord Ashcroft said the mayor of London was "doing a great job" and part of his appeal was that "he is a comedian".

But he said talk about Mr Johnson as a future leader was media-driven and not "relevant" to the party's primary goal of winning a majority at the next election.

"Those are long-term matters. If he ever had those ambitions, he has to get to Parliament, there has to be a leadership contest... you are talking a long timescale even if it is hypothetically possible."

Mr Cameron has insisted he does not envy Mr Johnson's "rock star" status, and says he accepts other people will be more popular than him while he is prime minister in difficult times for the country.

Asked on BBC Radio 4's Today programme what Mr Johnson could get him for his birthday, which he is celebrating on Tuesday, Mr Cameron said: "He's giving me a relatively light day, which is good of him.

"The point is, we are lucky in the Conservative Party to have some big and popular figures to take the message out across the country as well as having someone who is a first class Mayor of London."

Asked if Mr Johnson could be sent abroad to do something following his time as mayor, Mr Cameron quipped: "I'm not sure which country deserves him the most, but I will take that one away and think about it."

An opinion poll for The Observer gave Boris Johnson a net +30 rating among voters, compared with -21 for the prime minister.