Sue Gray, Sir Keir Starmer’s former Chief of Staff, is advising Andy Burnham on how to ‘transition to power’ if he topples the Prime Minister, sources have told The Mail on Sunday.

Lady Gray, ousted from No 10 in the early months of Sir Keir’s premiership, is understood to be helping the Manchester Mayor to sketch out the ‘configuration’ of a Burnham Downing Street if he wins the Makerfield by-election and then defeats Sir Keir in a leadership contest.

It comes as Tory MPs are making preparations for a snap election in the event that Mr Burnham wins No 10 and then decides to harness his ‘honeymoon’ period.

While Labour languishes as low as fourth in the opinion polls under Sir Keir’s leadership, a survey last week by More In Common put Labour on 30 per cent if Mr Burnham was in charge – with Nigel Farage’s Reform on 27 per cent and the Conservatives on 20 per cent.

On those figures, Kemi Badenoch’s party would no longer be the official Opposition.

Lady Gray is a longstanding friend of Mr Burnham, dating back to his time as a minister in Tony Blair’s Government, at the time when Lady Gray was rising through the ranks in the Cabinet Office.

Allies of Mr Burnham do not expect her to take any official role in Government because she is deemed to be too closely associated with the chaotic early days of the Starmer Government.

She was forced to resign in October 2024 after months of negative coverage, during which it was revealed Sir Keir was denied vital security briefings, with Lady Gray preventing the security services from gaining access to him.

No 10 consistently denied that tensions between Lady Gray and Starmer aide Morgan McSweeney were destabilising the Downing Street operation, but her departure became assured after it was revealed she had taken a higher salary than Sir Keir – as she was cutting the pay of other advisers.

She had previously been a senior civil servant who led the 2022 probe into the No10 Partygate scandal.

A source said: ‘Sue and Andy are old mates, and she spent a lot of time... trying to reduce the mutual suspicion between him and Keir. But don’t expect her to take a front-of-house role if he gets it.’

It comes as Tory MPs worried about the prospect of a snap election have started blitzing constituents. 

A Tory source said: ‘The fear is that it will catch us completely off guard. We are not ready.’

Calling an election would allow Mr Burnham to seek a mandate for the Left-wing policies he has advocated, such as wealth taxes.

One senior Labour MP said privately that if Mr Burnham was serious about delivering ‘change’, he should go to the country ‘as a matter of principle’.

And former minister Graham Stringer told The Mail on Sunday: ‘If Andy wants to be as radical as he claims, he needs to spell this out and, if he becomes PM, to get a mandate from the electorate.’

Asked about Lady Gray’s involvement in preparations for No 10, a source close to Mr Burnham responded last night, saying: ‘Andy is not getting ahead of himself – his full focus is on Makerfield.’

Mr Burnham was Gordon Brown’s health secretary in 2008 when the then-PM ‘bottled it’ by calling off an election announcement at the last minute. 

Many MPs believe the Manchester mayor would also decide not to go straight to the country.

One Labour insider said last night: ‘The Government currently has a working majority of 166 – you don’t give that up lightly.’ 

Another said they wanted an election ‘like a hole in the head’.

Lady Gray did not respond to a request for comment.

It came as victims of the Mid Staffordshire Hospital disaster – where NHS-run Stafford Hospital’s cost-cutting targets led to hundreds of preventable deaths – said then-health secretary Mr Burnham ‘should never be Prime Minister’.

The scandal saw patients left unwashed for months and families cleaning toilets for fear of disease. It claimed up to 1,200 lives.

But Mr Burnham ignored 81 demands for an inquiry from families, campaigners and MPs because it would be ‘distracting to managers’, and voted against it in Parliament. 

This week, he angered families further with his pronouncement that the British state has a ‘dangerous lack of accountability after major injustices’.

Julie Bailey, whose mother died in the tragedy, said: ‘[Burnham] should never be made Prime Minister. It would be a disaster for the country and the Labour Party.’