Labour's leadership crisis is feared to be causing a fresh delay to Britain's crucial defence plan.

Andy Burnham, who is almost certain to succeed Keir Starmer as Prime Minister, is said to want to decide himself on the vital multi-billion pound package.

The 10-year defence investment plan (DIP) was originally supposed to be published last autumn, but has been repeatedly delayed amid a furious Whitehall funding row.

The DIP will set out how new equipment and defence infrastructure will be funded over the coming decade and follows last June's publication of the wide-ranging strategic defence review.

Sir Keir has repeatedly promised the DIP will finally be published before he meets US President Donald Trump at a NATO summit in Turkey on 7 July.

But, with Sir Keir now set to be replaced by Mr Burnham in Downing Street, there are growing concerns the DIP won't materialise until a new premier is in No10.

Mr Burnham is reported to be keen to examine the plans himself, but - under a departure timetable set out by Sir Keir - the earliest he could become PM is 17 July.

It means Sir Keir could be facing the humiliating prospect of turning up to meet Britain's NATO allies next month without the DIP in place.

The furious Cabinet row over how to fund the DIP was the final straw for many Labour MPs who lost confidence in Sir Keir's leadership.

Earlier this month, John Healey dramatically quit as defence secretary as he fumed at Sir Keir for being 'unable' to find the billions of pounds needed to properly fund the DIP, while he claimed Chancellor Rachel Reeves was 'unwilling' to do so.

Despite the fears that the DIP will be delayed again until Mr Burnham is installed in No10, Sir Keir's allies have insisted it will still be published before the NATO summit.

Dan Jarvis, the new Defence Secretary who replaced Mr Healey, appeared to signal the DIP will come before 7 July as he entered Downing Street for Tuesday's Cabinet meeting.

It came after David Lammy, the Deputy Prime Minister, told MPs in the House of Commons on Monday: 'I can confirm that the DIP will be published before the NATO summit.

'And I think it is important that the Prime Minister is in post for that NATO summit.'

Tory leader Kemi Badenoch criticised Labour for leaving Britain 'in limbo' while the country awaits a new PM.

She told Times Radio on Tuesday: 'We are in limbo. I'm quite concerned that Andy Burnham looks to be wanting a summer holiday, Keir Starmer a farewell tour.

'But there are some serious issues, not least of all, the lack of a Defence Investment Plan, which is what caused this final crisis for Keir Starmer with his defence secretary resigning.'

Mrs Badenoch repeated her call for the Government to cut benefits spending in order to properly fund the DIP, adding: 'If Andy Burnham will not bring down the welfare bill to pay for defence, then there should be a general election.'