Keir Starmer: Investigations into Boris Johnson's flat could be 'over in five minutes' if he revealed who initially paid

Investigations into the financing of the refurbishment of Boris Johnson's Downing Street flat could be "over in five minutes" if he revealed who initially paid for the renovations, Sir Keir Starmer has said.

The Electoral Commission announced on Wednesday that it will launch a "formal investigation" into the Number 11 flat's pricey makeover.

It comes after ITV News Political Editor Robert Peston revealed exclusively that costs were covered in the form of a loan from the Tory Party.Cabinet Secretary Simon Case has also said he will produce a report on the renovation.

On ITV's Peston show, Labour party leader Sir Keir said: "Those investigations could be over in five minutes if the prime minister just answered the question, 'who payed for it in the first place?'".

Sir Keir had put the question to Boris Johnson earlier on Wednesday at PMQs but the prime minister refused to directly answer the Labour leader's questions.On Wednesday it was announced that former private secretary to the Queen, Lord Geidt, has been appointed to the vacant role of independent adviser on ministers' interests.

However, it is still the prime minister who has the final decision on whether a breach of the ministerial code warrants sanctions, meaning he would be the one to decide whether or not to punish himself.

Sir Keir told presenter Robert Peston that if he were in Mr Johnson's position, he would allow an independent person to adjudicate on whether he should resign.

He added: "If I were prime minister, I would make it my mission to clean up Westminster.

"I had to deal with prosecuting MPs who broke expenses rules - I know what tough decisions look like."

Sir Keir also commented on allegations that the prime m inister said he would rather have “bodies pile high in their thousands” than implement a third coronavirus lockdown.

When asked how he would respond if the PM's former chief aide Dominic Cummings said the comments were, in fact, made, the Leader of the Opposition said he would have to "wait and see".

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"It's not much of a choice, is it, between Dominic Cummings and Boris Johnson as to where the truth lies on any issue," he said.

A war of words between Mr Johnson and Mr Cummings has dominated media headlines over the past week, from the PM saying Mr Cummings leaked his texts, to the ex-chief aide claiming Mr Johnson made "unethical" moves when it came to his flat.

Ministers are now concerned at what Mr Cummings may say when he gives evidence to MPs investigating the government’s response to the pandemic next month.