No 10 claims Starmer did not know Mandelson failed security vetting until this week – as it happened

Keir Starmer inside No.10 Downing Street Photograph: Leon Neal/AFP/Getty Images

6.54pm BST

Evening summary

• Peter Mandelson failed his security vetting clearance but the decision was overruled by the Foreign Office to ensure he could take up his post as ambassador to the US, an investigation by the Guardian can reveal.

• The Conservatives, Reform UK and the Greens have all said that Keir Starmer should resign in the light of the Guardian revelations because he misled MPs, or lied to the public, about the Mandelson appointment. The Liberal Democrats have also said that Starmer should quit if it is established that he has lied. Starmer will find it hard to argue that he was being honest when he said at a press conference in February that Mandelson got “clearance” from the vetting process (see 4.35pm, 4.43pm and 5.11pm) if people do not believe he only found out about the vetting this week. (See next point.) But he may find it easier to justify his vague comment in the Commons about “due process” being followed, because the process does allow vetting decisions to be overruled (see 4.35pm).

• No. 10 released a statement that said Starmer was not aware that Mandelson had failed the security vetting until this week. That is likely to raise further questions about who knew – and also why Starmer was not informed.

• The SNP will cap supermarket prices for essential goods such as bread and milk if it retains power, John Swinney has pledged, after describing the cost of living as “the defining issue of this election”.

For a full list of all the stories covered on the blog today, do scroll through the list of key event headlines near the top of the blog.

6.40pm BST

SNP's Westminster leader asks independent adviser on ministerial standards to investigate whether Starmer misled the public

Stephen Flynn, the SNP’s Westminster leader, has written to the independent adviser on ministerial standards, Laurie Magnus, to demand that he investigate whether Keir Starmer misled the public over Peter Mandelson.

In a statement Flynn accused Starmer of “making contradictory claims about the process followed when appointing him to the highest diplomatic office in these isles.”

He added:

Today Keir Starmer has been caught in what appears to be nothing less than a shocking lie – he claimed Peter Mandelson passed security vetting when we now know the very opposite to be true. These new revelations are the most serious yet for the Prime Minister.

No 10 said that Starmer was only made aware that Mandelson failed his vetting this week (see 6.09pm).