Alloa and Grangemouth MP Brian Leishman has called for the Prime Minister to consider resigning.
Sir Keir Starmer is under pressure after the appointment of Lord Mandelson as US ambassador.
Chief of staff Morgan McSweeney has resigned.
In a statement on X, Leishman says the Prime Minister should "consider following McSweeney's lead".
It reads:
"McSweeney was at the heart of the political mistakes made since the General Election.
He helped create this factionalism in the Labour Party.
The country & party will be better off after today.
The PM must consider following McSweeney’s lead one last time & doing the same."
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