Plans to replace the Royal Navy's ageing destroyers and frigates are set to be shelved in favour of drones and other autonomous weapons systems under the Government's long-delayed defence investment plan, according to reports. The UK's commandos will meanwhile be promised £500 million as part of the blueprint, with high-speed boats and strike drones for the elite force as Britain shifts its focus to modern warfare in the face of growing Russian activity in the High North.Officials say Dan Jarvis has 'shifted' the focus of spending in the defence investment plan (Dip) since he became Defence Secretary earlier this month towards providing kit to troops on the front line. He is also understood to have secured around £1 billion extra for the plan in negotiations with the Treasury, taking the overall settlement to as much as £15 billion, according to the Sunday Times.The £13.5 billion offer previously on the table prompted his predecessor John Healey to resign.The newspaper reported that funding for up to eight planned Type 83 destroyers and five Type 32 frigates will no longer feature in the Dip, with autonomous and uncrewed systems instead taking priority. Some form of new crewed vessel is still expected to be commissioned in the future. Warfighting readiness and integrated autonomy - including equipment like drones, uncrewed vessels and land vehicles - are expected to be the two key priorities in the 'refreshed' version of the blueprint for future-proofing the armed forces. British Army soldiers from 3 Rifles watch a single-rotor helicopter style Ghost drone, which operates via global mobile networks and can be remotely piloted from anywhere in the world Royal Marine commandos helped intercept the tanker Smyrtos in the Channel in the first UK-led operation to capture a sanctioned ship earlier this month Dan Jarvis (right) was named as the new defence secretary on Thursday following John Healey's resignationOfficials say the funding will partly go towards new high-speed commando insertion craft – special vessels used to covertly transport troops from the rapid-response force – which could be used for operations including the seizure of Russian shadow fleet vessels.It comes after Royal Marine commandos helped intercept the tanker Smyrtos in the Channel early in the first UK-led operation to capture a sanctioned ship earlier this month.Meanwhile, around £100 million will be committed to new technologies, including uncrewed vessels, 'next-generation communications' and strike drones, they said.The Dip was originally due last year, but has been held back amid wrangling within Government over the amount of money required to finance the military.Mr Healey quit his Cabinet post earlier this month because the blueprint was only due to provide £13.5 billion extra investment, which he said fell 'well short' of what was needed.The Ministry of Defence said the plan will see the UK work with Norway, a Nato ally with which Britain has partnered amid increased Russian submarine activity in the High North.The Defence Secretary told reporters on Saturday that 'real progress' had been made in recent days, but work was ongoing to 'get it right' ahead of its expected publication before July 7. Speaking on a visit to Ukraine, Chancellor Rachel Reeves, who is widely tipped for the sack next month, defended her spending record in the Treasury'I've been working very hard since I was appointed to satisfy myself that we've got the right resource and the right mix of capabilities,' he said.'I have a responsibility to make sure I get it right and that is what I'm working to achieve.'Outgoing Prime Minister Sir Keir Starmer is set to press ahead with publishing the Dip before the July 7 Nato summit, despite major policy and spending commitments being paused across Government more widely in preparation for the transition of power in the coming weeks.The move could potentially cause friction with his likely successor, Andy Burnham, who may want to have the final say on future funding for the military.Mr Jarvis said plans to prioritise the commandos would help give them 'the equipment they need to stay ahead of our adversaries and defend us.''The defence investment plan will prioritise getting the latest kit into the hands of our frontline forces, so they can continue their vital work in an increasingly dangerous world,' he added.Mr Jarvis, who served as mayor of the Sheffield City Region while Mr Burnham was Greater Manchester mayor, has joined other Cabinet ministers in publicly backing the Makerfield MP as the likely next prime minister.'He was an exceptional mayor of Greater Manchester and I think he will be an excellent prime minister. He understands the importance of national security and making sure that we've got the right amount of resource to invest in our armed forces,' he said.'That is a process that is absolutely under way, but it is on the back of a commitment already to historic levels of defence funding.'Yes, we want to do more, and the Dip will deliver that, and, yes, we want to go further, the other side of the Dip.'That is well understood by Andy Burnham. It's well understood by the current Prime Minister. It's my job to deliver for defence and that's what I'm working hard to do.'Chancellor Rachel Reeves also backed Burnham, saying he will 'almost certainly' be the next Prime Minister.She made the comment while speaking during a visit to Ukraine, where she also said the Government's defence investment plan would be published 'imminently'.She said it would include more spending and set out how Britain would prepare for future conflicts.The Chancellor, who is widely tipped to be sacked in next month's reshuffle, also defended her time in the Treasury.She said she had overseen £120 billion of investment in defence, energy, digital infrastructure and transport links across the UK.Ms Reeves has worked closely with Sir Keir Starmer for years and is the second most unpopular politician in the country after the Prime Minister.She has also been at the centre of some of Labour's most controversial decisions, including the cut to winter fuel payments and the botched welfare reforms that sparked a Labour mutiny.Earlier this week, she said Mr Burnham would be 'great in No.10', in what critics viewed as a last-ditch attempt to shore up her position.Setting out her defence plans, she told reporters: 'The defence investment plan hasn't yet been published, and what I can tell people is that plan will involve more money.'I'm already the Chancellor that's overseen the biggest uplift in defence spending since the end of the Cold War, but recognising the scale of the challenge we face today, we need to increase that amount further.'We'll be doing so in setting that out imminently, and certainly ahead of the Nato summit in Ankara, but the new prime minister, who is almost certainly going to be Andy Burnham, will absolutely stand by Ukraine as the UK has done both as a Government and as a people ever since Russia's invasion.'She added that the plan would be 'a detailed account of how we're going to spend that additional money to meet the scale of the challenges we face today, and crucially, the defence investment plan will be about the wars of tomorrow and today, not of the past'.