It is one of the more private dilemmas facing Boris Johnson as he prepares for life at Number 10: what to do about his girlfriend Carrie Symonds.
With the 55-year-old expected to be unveiled as the next Prime Minister on Tuesday, speculation is mounting as to whether the 31-year-old former Tory aide, will accompany him through Downing Street's famous black door.
Friends have told The Sunday Telegraph that the couple will continue living together if Johnson becomes Prime Minister. While Johnson will spend the week choosing his Cabinet and being congratulated by world leaders if he wins the Tory ballot, Symonds is said to be planning to keep a low profile.
The former Conservative Party director of communications will not be given a political role and intends to keep her job as a senior adviser at Oceana, a US-based environmental campaign group, The Telegraph understands.
Some advisers have suggested that Johnson should "walk into Downing St with Carrie on his arm" because it would be "very bold, and very Boris."
"This is the biggest headache we've got," one Boris backer said.
"The camp is divided but the majority believe she should be kept in the background. It's very difficult. Ultimately it's for Boris to decide. If he loves her and intends to marry her then Carrie should be by his side."
Johnson is still married to his second wife Marina, the mother of four of his children. Friends have described the couple as "very loved up" and insist they intend to marry once his divorce comes through, despite a domestic row last month which was recorded by neighbours.
Symonds' close friend Nimco Ali last month revealed that the "expectation" was for the couple to get married, adding: "They are happy and good for each other."
But as one insider pointed out, it isn't just the protocol problems of having an unmarried couple living in Downing St that are causing concerns but some have even suggested Symonds is keen to see some of her allies secure jobs in the new administration.
Johnson has resolutely refused to discuss his private life since he first entered politics in 2001.
But as one insider explained: "Boris does a significant pull of loyalty to her. I think it's going to prove difficult for him not to take her in. And in not taking her in he also creates a story."
The source said the new Number 10 operation would be at pains to avoid "a Francois Hollande" situation where Johnson was "turning up to some front door in Surbiton on his bike," adding: "This isn't Love Actually."
Another insider suggested some of the opposition to Carrie moving into Downing St was based on "jealously and a degree of insecurity".
Whether she goes through the front door or the back door, the general consensus appears to be that Symonds intends to make Number 10 her home one way or another.
As one well-placed insider put it: "She might not go in through the front door but she'll be in the building, no doubt about it."
A spokesman for Johnson declined to comment.