Jeremy Corbyn has vowed not to retire as Labour leader and said he was inspired by his father to continue working beyond the pensionable age.

He said his age, 66, was no barrier to appealing to younger voters and dismissed the prospect of quitting.

Corbyn’s opponents have questioned his stamina but he struck a defiant note, saying: “I’ve never gone through life with the intention of retiring. My dad didn’t retire. He died working. Not because he was forced to but because he wanted to. It’s a family thing”.

Corbyn was speaking to the Derby Telegraph as part of a visit to discuss Rolls-Royce engineering jobs in the city.

He insisted his plans to scrap the use of nuclear warheads on Trident submarines would not hit jobs at Rolls-Royce, where the reactors that power the vessels are manufactured.

He also defended his longstanding opposition to Trident over the course of 33 years as an MP.

“I have a life-time view that nuclear weapons are not a defence against anything. They are weapons of mass destruction and if ever used would only lead to greater mass destruction.”

He was speaking as it emerged the Commons vote on Trident renewal could be delayed until after the EU referendum, which is expected in June at the earliest.

It is thought David Cameron hopes to capitalise on Labour’s long-running internal debate on the weapons system by allowing it to continue through the summer.

Earlier this week Emily Thornberry, the shadow Defence Secretary, was criticised for an “embarrassing” speech at PLP meeting where she proposed unilateral disarmament – but she is in lockstep with Corbyn on the issue of nuclear weapons.