Jeremy Corbyn has slammed the chief of defence for "taking sides" in the debate over the UK's Trident nuclear weapons programme.
On Sunday morning, Gen Sir Nicholas Houghton criticised Corbyn's anti-nuclear stance, saying he would "worry" if the Labour leader became prime minister as it would risk undermining the nuclear deterrent. Corbyn has previously said he would never use nuclear weapons if he was elected prime minister.
Ahead of a Remembrance Day service in his constituency in Islington North, Corbyn said Houghton's words were a matter of "serious concern" and that he intends to write a letter of complaint to defence secretary Michael Fallon.
"It is a matter of serious concern that the chief of the defence staff has today intervened directly in issues of political dispute," said Corbyn. "It is essential in a democracy that the military remains politically neutral at all times. By publicly taking sides in current political arguments, Sir Nicholas Houghton has clearly breached that constitutional principle.
"Accordingly, I am writing to the defence secretary to ask him to take action to ensure that the neutrality of the armed forces is upheld."
Houghton told the BBC's Andrew Marr Show on Sunday: "It would worry me if that thought was translated into power, as it were. There are a couple of hurdles to cross before we get to that [Corbyn being prime minister], but the reason I say this, and it is not based on a personal thing at all, it is purely based on the credibility of deterrence.
"The whole thing about deterrence rests on the credibility of its use. When people say 'you are never going to use the deterrent', what I say is you use the deterrent every second, of every minute, of every day."