Tories threaten showdown in Commons if Keir Starmer won't come clean about Mandelson vetting fiasco - as Kemi sets deadline for PM to release all information about his appointment as US ambassador

By GABRIEL MILLARD-CLOTHIER, POLITICAL REPORTER Published: 00:03, 19 April 2026 | Updated: 00:09, 19 April 2026 Kemi Badenoch will aim to force a Commons showdown to pile pressure on the Prime Minister over the Peter Mandelson vetting fiasco. The Tory leader has given Sir Keir Starmer until Friday to release all information about Mandelson’s appointment as US ambassador – and vowed to use ‘every possible parliamentary procedure’ if No 10 does not comply. Conservatives have written to the Commons Speaker to demand a Privileges Committee inquiry, the same approach Sir Keir used to dismantle Boris Johnson’s leadership. This would see a group of MPs investigating whether the Prime Minister knowingly misled the Commons when he repeatedly claimed due process had been followed over Mandelson’s appointment. It follows the revelation that Sir Keir was told on Tuesday evening the New Labour grandee had been appointed despite failing his security vetting, only for the decision to be overruled. But he said nothing until the news leaked two days later, including at Prime Minister’s Questions on Wednesday. MPs say this was a breach of ministerial rules. Sir Keir has insisted he will set out the full story in a Commons statement tomorrow, but Conservatives do not believe him. One leading Tory MP told The Mail on Sunday: ‘Starmer has lied – we must get to the bottom of this once and for all. The only way is to force the Prime Minister to come clean in Parliament on our terms.’ Kemi Badenoch (pictured) has given Sir Keir Starmer until Friday to release all information about Mandelson’s appointment as US ambassador – and vowed to use ‘every possible parliamentary procedure’ if No 10 does not comply Conservatives have written to the Commons Speaker to demand a Privileges Committee inquiry, the same approach Sir Keir (pictured) used to dismantle Boris Johnson ’s leadership Sir Keir previously stated that Peter Mandelson (pictured) passed security vetting, and told the Commons that 'due process' was followed A Privileges Committee inquiry into Partygate – unlawful gatherings in Downing Street during the pandemic – heavily criticised Mr Johnson, triggering his resignation as an MP.  Parliamentary sources describe it as the ‘nuclear option’. The Tories may also use a Standing Order 24 (S024) debate to encourage Labour MPs to vote against the PM. The emergency debates allow the opposition to dictate the terms, and would put Sir Keir on the back foot.  The method was often used by Sir Keir in opposition to force tricky votes on Brexit.  A Tory spokesman said: ‘This is speculation. We are keeping our plans private.’ No comments have so far been submitted. Why not be the first to send us your thoughts, or debate this issue live on our message boards. By posting your comment you agree to our house rules. Do you want to automatically post your MailOnline comments to your Facebook Timeline? Your comment will be posted to MailOnline as usual. Do you want to automatically post your MailOnline comments to your Facebook Timeline? Your comment will be posted to MailOnline as usual We will automatically post your comment and a link to the news story to your Facebook timeline at the same time it is posted on MailOnline. To do this we will link your MailOnline account with your Facebook account. We’ll ask you to confirm this for your first post to Facebook. You can choose on each post whether you would like it to be posted to Facebook. Your details from Facebook will be used to provide you with tailored content, marketing and ads in line with our Privacy Policy.