Downing Street has refused to comment on reports the wallpaper in the Prime Minister’s lavishly furnished flat is falling down.

Work on the No 11 apartment Boris Johnson shares with fiancee Carrie Symonds is the subject of a series of investigations.

Mr Johnson has insisted that he has paid for all the works himself but has refused to say whether he received an initial loan to cover them.

The Daily Mail reported that the £840-a-roll luxury wallpaper used in the redecoration is now peeling off.

The newspaper reported that the gold-coloured paper is a heavyweight design compared to mass-market wall coverings.

Asked about the issues with the decor, the Prime Minister’s official spokesman: “I’m not going to get into that sort of speculation.”

Further details about the refurbishment – which reportedly features products from interior designer Lulu Lytle’s Soane Britain firm – are expected later this month.

Ministerial standards watchdog Lord Geidt said he is “determined” to publish the long-overdue list of ministers’ interests before the end of May.

The crossbench peer told MPs that alongside the list he will publish his report into the declaration of any donations the Prime Minister received to help cover the costs of the No 11 revamp.

Whitehall’s senior mandarin, Simon Case, is also reviewing the Downing Street refurbishment, while the Electoral Commission is investigating whether the Conservative Party broke any laws over the funding of the work.

Mr Johnson has insisted the row over the flat is a “farrago of nonsense”.