Boris Johnson blamed failure to disclose messages over flat revamp because they were on old phone

Prime Minister Boris Johnson is said to have blamed the mix-up on changing phones

The Prime Minister has offered a “humble and sincere apology” to his standards adviser for not disclosing an exchange of messages with a Tory peer where he discussed the funding of the refurbishment of his Downing Street flat.

Mr Johnson told Lord Geidt, his adviser on ministerial standards, the messages had been on an old phone that he had to stop using due to “security issues” and therefore he “did not have access to my previous device and did not recall the message exchange”.

Lord Geidt said the failure to alert him to the WhatsApp messages exchanged with Tory donor Lord Brownlow had been “unwise”, but still cleared Mr Johnson again.

In a letter to the Prime Minister, the peer said: “The new disclosure did not, in fact, result in change to my original assessment of your interests insofar as they related to the ministerial code.

“It did, however, expose a signal deficiency in the standards upon which the independent adviser and, by extension, the Prime Minister have an absolute right to rely in establishing the truth in such matters.

“Indeed, the episode shook my confidence precisely because potential and real failures of process occurred in more than one part of the apparatus of government. I am very grateful to have your apology for these shortcomings and to know of your determination to prevent such a situation from happening again.”

It comes despite Mr Johnson previously saying he had no knowledge of the payments until immediately prior to media reports in February last year.

Mr Johnson said he did not have access to his previous mobile phone and “did not recall the message exchange”.

But he said: “A fuller explanation of the circumstances should have been provided at the time of your investigation. I am sorry we did not do so.”

Responding, SNP deputy Westminster leader Kirsten Oswald said: “Boris Johnson’s sleazy Tory government is the most corrupt in decades. If the Prime Minister had a shred of decency or integrity, he would have resigned months ago – but he doesn’t.

“Johnson has been at the rotten core of scandal after scandal – handing peerages to Tory donors, soliciting dodgy donations for holidays and home renovations, giving special access, public contracts, jobs and tax breaks to his friends and cronies, and breaking the rules of public office.”

Deputy Labour leader Angela Rayner said: "The Ministerial Code requires ministers to act with transparency and honesty. It is simply impossible to read these exchanges and conclude that the Prime Minister has not breached these aspects of the code.

"Once again, by attempting to hide the truth, Boris Johnson undermines his own office.

"The Prime Minister’s pathetic excuses will fool no one and this is just the latest in a long line of sorry episodes.

“The British public can't WhatsApp a wealthy donor to open their wallets on request, and the least they deserve is transparency about who’s bankrolling their Prime Minister.”

The Electoral Commission fined the Conservatives £17,800 after it found the party had not followed the law over donations by Lord Brownlow to help cover the renovations, with costs exceeding £112,500.