Why did Prime Minister say nothing for days? Starmer faces new claims of rule breaking over failure to admit scandal straight away

By MARTIN BECKFORD, POLICY EDITOR Published: 00:17, 18 April 2026 | Updated: 00:26, 18 April 2026 Keir Starmer is facing new questions about why he kept quiet about the Peter Mandelson vetting fiasco. The Prime Minister stands accused of breaking ministerial rules by not immediately informing MPs of the latest scandal. He has admitted that he was told on Tuesday evening that the New Labour grandee had been appointed US Ambassador despite failing his security vetting, only for the decision to be overruled. But he said nothing for the best part of a day-and-a-half before the news leaked. That included his weekly outing in the Commons at Prime Minister's Questions on Wednesday. And when the story broke on Thursday afternoon, it was not until 6pm that the Government issued a response. Sir Keir will not address the Commons until Monday afternoon, six days after learning that he had been wrong to assure MPs previously that the 'full due process' had been followed when Mandelson was sent to Washington early last year. This is despite the Ministerial Code stating: 'It is of paramount importance that ministers give accurate and truthful information to Parliament, correcting any inadvertent error at the earliest opportunity.' It emerged on Friday night that senior officials were indeed concerned ministers had misled Parliament. Keir Starmer is facing new questions about why he kept quiet about the Peter Mandelson (pictured together on February 27, 2025) vetting fiasco The Foreign Office's top civil servant Sir Olly Robbins (pictured) was sacked after his department failed to inform Starmer that Lord Mandelson had failed the security vetting An email published by the Government summarising the meeting in No 10 on Tuesday night – written by Dan York-Smith, principal private secretary to the Prime Minister – stated: 'Our advice to the PM was that further fact-finding was required, to understand the Foreign, Commonwealth and Development Office decision-making process and reasons for granting clearance and to determine whether ministers, having been provided (incorrectly) with assurances about the process, had inadvertently misled Parliament when commenting on the process which had been followed.' The PM has now been reported to his ethics adviser Sir Laurie Magnus for a potential breach of the rules. Liberal Democrat MP Lisa Smart said: 'The Prime Minister failed to tell Parliament that he knew Mandelson had been denied vetting on Wednesday, presumably crossing his fingers and hoping the truth would not come out.  'What a shameful way for a Prime Minister to behave. To stand in front of the dispatch box and deny Parliament such crucial information looks like a serious breach of ministerial code. 'That's why I've written to the ethics adviser to report this breach and ask him to investigate at the earliest opportunity.' Senior Tory MP Neil O'Brien said: 'The Ministerial Code could not be clearer on this. The Prime Minister, having misled the House, is supposed to correct the record as soon as he possibly can.  'Yet he went through Prime Minister's Questions without disclosing something he admits he knew on Tuesday. The rules are very clear and he has broken them.' Mr O'Brien added: 'He was caught, he didn't admit it. It wouldn't have come out without The Guardian [newspaper] reporting it first.'  Sir Keir is also facing the prospect of a parliamentary investigation similar to the one Boris Johnson was subjected to over the 'Partygate' pandemic scandal. The Lib Dems said the privileges committee should look into what the Prime Minister knew about Lord Mandelson's vetting failure and whether he intentionally misled MPs. Party leader Sir Ed Davey said: 'We need to get to the bottom of exactly what Keir Starmer knew when, and whether he intentionally misled Parliament over this appalling scandal. 'The public deserves the truth, not another cover-up. If it turns out Starmer was aware at the time that Mandelson's security vetting was overruled, that would represent a major abuse of power and a betrayal of the national interest.' The Prime Minister's right-hand man insisted yesterday that Sir Keir wanted to update MPs as soon as he could but needed to get the full facts first. Darren Jones, chief secretary to the Prime Minister, told BBC Radio 4's Today programme: 'As soon as the Prime Minister was informed on Tuesday evening that this had happened, he requested the Cabinet Secretary to provide him with a detailed list of the facts: what happened when, who did what and how do we explain the situation. 'The reason he asked for those facts is because he told the Cabinet Secretary on Tuesday evening that he was going to go to the House of Commons to provide this information to Parliament and to the public. 'But it is right therefore that he had all of those facts in front of him before he did so, because if he went before he'd had those facts and inadvertently made a mistake, Parliament would rightly criticise the Prime Minister for doing that.' The comments below have been moderated in advance. The views expressed in the contents above are those of our users and do not necessarily reflect the views of MailOnline. 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