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
A pensioner who made neighbours' lives a misery, including displaying images of Miss Piggy to torment an overweight woman, has been jailed.
A series of relaxed new portrait pictures of the Duchess of Cambridge have been released, and will go on public display from Sunday.
14-year-old Jasmine Elcock is the fourth Britain's Got Talent 'golden buzzer' act after leaving Ant in tears with her performance.