Mayor of London should not be Boris Johnson's last job in politics, Prime Minister David Cameron said yesterday.
Mr Cameron brushed aside speculation that he was feeling threatened by the prospect of Mr Johnson seeking to return to the House of Commons and challenging him for the leadership of the Conservative Party.
He insisted he had "the opposite of tall poppy syndrome", and wanted to see high-profile Conservatives like Mr Johnson grabbing headlines.
A poll on the first day of the Tory conference in Birmingham suggested that voters prefer the London Mayor to Mr Cameron by a wide margin.
The survey by pollsters Opinium for The Observer gave Mr Johnson a net +30 rating compared to -21 for the Prime Minister.
The poll also showed a strong pick-up in Ed Miliband's approval rating, which has risen to -10 following last week's Labour Party conference – his best showing in an Opinium poll.
Deputy Prime Minister Nick Clegg, however, continues to languish on -48.
Asked on BBC1's Andrew Marr Show whether he felt threatened by Mr Johnson, Mr Cameron said: "I think he is a fantastic London Mayor. I think he does an excellent job. I think he is an enormous credit to the Conservative Party.
"I have got the opposite of tall poppy syndrome. I like having other people in the Conservative Party who are popular, who get out there, talk our message and explain our vision and values.
"Boris is fantastic like that. He is one of those politicians people warm to and I think it is great that we have in our party figures like that."
Mr Cameron was asked whether he would invite Mr Johnson to join his Government when he completes his stint as London Mayor.
"I have said to Boris: 'Once you have done your job as London Mayor, don't think your job in politics is over'," replied the Prime Minister.
"I think he has got a huge amount to offer, a huge amount to give and I encourage him to do that.
"I think it is great that the greatest city in the world has got such a good mayor."
Yesterday's poll suggested that Labour enjoyed only a small post-conference bounce, up two points on 41%, an 11-point lead over the Tories, who are up one point on 30%, with the Liberal Democrats on 9%.