Cyber rather than battlefield warfare will be prioritised in the UK's national security review, it has been reported.
The Ministry of Defence (MoD) has been told that the Armed Forces will not get any extra money, with funds instead being focused on countering cyber-attacks, the Telegraph reported.
Tensions are building within the MoD over the prospect of defence spending cuts which will be discussed this week between the chancellor, Philip Hammond and the defence secretary, Gavin Williamson.
New to the post after the resignation of Sir Michael Fallon, Williamson is said to want an extra £2bn to stave off the first round of cuts.
But the Telegraph reported how national security adviser Mark Sedwill has told the MoD it will not get any more than its current £36bn-a-year budget, despite its request for £20bn over the next decade.
One ministerial source told the paper Sedwill "is determined to screw over the MoD" so as to get more cash to tackle cyber threats and that "the problem is the NSA (Sedwill) is driving a 'within-the-costs-envelope' approach at everyone."
Among the cuts mooted, the MoD has proposed sacking 1,000 marines, cutting two ships and slowing down an order for stealth jets, with the Army set to be cut to fewer than 70,000.
However there is concern at how Britain will be able to defend itself, especially in light of an increased perceived threat from Russia. General Sir Richard Barrons, a former commander, said in July that top brass and ministers should discuss the state of Britain's military. Lord Boyce, a former chief of the defence staff has said that the military was being weakened by cuts.
An MoD spokesman said: "No decisions have been made and any discussion of the options is pure speculation."
A Treasury spokesman said: "We cannot comment on speculation on meetings between cabinet ministers."