Prime Minister David Cameron said he and Boris Johnson have discussed a possible return to Parliament for the London Mayor, but stressed a decision has yet to be taken.
Asked how likely a return was, Mr Cameron told BBC Radio 4's Today programme, "That's up to Boris."
He continued: "I've had this conversation with Boris and my message to him is 'You're a brilliant Mayor of London, you've done a great job, you've got a lot more to give to public life, and it would be great to have you back in the House of Commons at some stage, contributing to public life'.
"But that's up to him, but I'll certainly be giving him a warm welcome."
More top news
Fans can finally have their first look at Jared Leto's incarnation of the classic villain in 2016's Suicide Squad
Labour is promising to reverse the Conservative policy of privatisation in the NHS which it claims is creating longer waiting times.
The Queen and senior members of the monarchy will attend services around the world to commemorate the centenary of the battle of Gallipoli.