David Cameron has denied that he envies Boris Johnson's "rock star status" after the London Mayor was mobbed on his arrival at the Conservative conference in Birmingham.

Mr Johnson was greeted by ranks of cameras and passers-by chanting "Boris! Boris!" as he arrived in Birmingham, while a 1,000-strong audience hung on his every word at a rally on Monday night.

The conference has been dominated by gossip in the corridors and bars over whether Mr Johnson could succeed Mr Cameron as leader, following polls which suggest he would give the party a big boost in the polls, where the Tories currently trail Labour by up to 10 points.

The mayor's platform address to delegates today, followed by a round of media interviews, is expected to win him even more attention.

Mr Cameron said he is resigned to the fact that other people will be more popular than him while he is Prime Minister in difficult times for the country.

Asked by ITV1's Daybreak whether he was worried by the "hero-worship" of Mr Johnson, he replied: "No. I think it is great that we have got someone with rock star status in the Tory Party.

"I think it's fantastic that he can come to Birmingham, he is a very successful Mayor of London, he is doing a great job.

"I have got the opposite of tall poppy syndrome. I want to have big stars in the Conservative Party that can carry our message to the country, and Boris is definitely one of those."

He said he was unconcerned by polls suggesting that Mr Johnson is more popular than him with voters.

"There are lots of people that are more popular than me in this world, because I have to be the one who takes the difficult decisions on behalf of the country to recover us from the dreadful state that Labour left us in. That's just life, but in politics what matters is you do your duty, you do the right thing for your country."