Labour MPs urge Prime Minister to end 'contagious disease of disharmony' in No 10 amid feud between Sue Gray and rival aide Morgan McSweeney

Sir Keir Starmer faced demands from Labour MPs last night to end the damaging power battle inside No 10 or see 'disharmony' spread across his party.

The Prime Minister was openly urged to 'sort out' the feud between his chief of staff Sue Gray and rival aide Morgan McSweeney.

In a grim warning to Sir Keir, former Cabinet Office minister Graham Stringer said: 'Disharmony is a contagious disease. The Prime Minister needs to sort out and stop this squabbling very quickly. It's bound to damage the Government if it isn't resolved.'

Another Labour MP said privately: 'Keir has to intervene – he cannot let this fester.'

No 10 responded last night by insisting there was no feud between the two powerful aides at the heart of the new PM's operation.

The Prime Minister was openly urged to 'sort out' the feud between his chief of staff Sue Gray (pictured) and rival aide Morgan McSweeney

The Prime Minister was openly urged to 'sort out' the feud between his chief of staff Sue Gray (pictured) and rival aide Morgan McSweeney

Sources insist Ms Gray and Mr McSweeney (pictured) are locked in a power struggle carried over from their days working for Sir Keir in opposition

Sources insist Ms Gray and Mr McSweeney (pictured) are locked in a power struggle carried over from their days working for Sir Keir in opposition

In a grim warning to Sir Keir, former Cabinet minister Graham Stringer (pictured) said: 'Disharmony is a contagious disease. The Prime Minister needs to sort out and stop this squabbling very quickly. It's bound to damage the Government if it isn't resolved'

In a grim warning to Sir Keir, former Cabinet minister Graham Stringer (pictured) said: 'Disharmony is a contagious disease. The Prime Minister needs to sort out and stop this squabbling very quickly. It's bound to damage the Government if it isn't resolved'

But sources insist Ms Gray and Mr McSweeney are locked in a power struggle carried over from their days working for Sir Keir in opposition.

Amid reports that former civil servant Ms Gray thought Sir Keir's inner circle was too male, it has been seen as a battle between her 'girls' gang' and Mr McSweeney's 'boys' brigade'.

Last night, sources suggested that Luke Sullivan, a key aide in Sir Keir's opposition team, was a victim of that rivalry amid reports that Ms Gray denied him a post in Downing Street.

There were even claims yesterday – denied as 'untrue' by Downing Street – that she was trying to restrict strategy aide Mr McSweeney's access to senior civil servants.

When she herself was a civil servant, Ms Gray, 66, presided over the 'Partygate' inquiry into lockdown parties in Downing Street when Boris Johnson was PM and which Boris allies say played a decisive role in his resignation.

Keir Starmer speaks during a news conference at Downing Street on Thursday, August 1

Keir Starmer speaks during a news conference at Downing Street on Thursday, August 1

And such is her perceived prowess at preparing Labour for power and advising Sir Keir in Downing Street that she is now widely referred to as 'the real Deputy PM'.

But only last week, The Mail on Sunday revealed claims that the PM was being denied vital security briefings because his chief of staff was blocking access to him.

There were fresh claims yesterday that Ms Gray, a civil servant of long standing before joining Sir Keir's team in opposition, had previously withheld information from ministers at another government department she had worked at.

However, No 10 has denied that the chief of staff was restricting national security officials access to the PM.