The defence secretary, Wes Streeting, says he started stockpiling food and water weeks ago in case of a national emergency as he talked up the threats to the UK and said his department had already begun ramping up its spending in response.

Streeting spoke after the chancellor, John Healey, said he wanted defence spending to reach 3% of GDP by 2030 and 3.5% by 2035; having already asked Whitehall departments to find 1% cuts in their budgets for long-term investment to fund defence spending.

“I’m glad the message is getting through because my mum got in touch and said ‘payday is coming up, how much do you think I need to buy because I’m just budgeting to the end of the month?’ I’m glad that people are beginning to think about their own household resilience, making sure we’ve got sufficient supplies of bottled water, canned goods, battery-powered torches. These are all just commonsense things for the everyday challenges,” Streeting told the Times.

The defence secretary said he has bottled water, a first aid kit and a battery-powered torch on standby. He added that he is stockpiling baked beans, sweetcorn, red kidney beans, tuna, protein bars and nuts. Streeting, who recently urged all Britons to follow suit, said he started setting aside the supplies because he wanted to “lead by example”.

And he told the Times he was determined the UK should be able to deter its adversaries and “should deterrence fail, to be ready to defeat them”. Streeting said: “That is the core job. We should never lose sight of that,” adding that any additional spending must be done carefully. “Spending more money badly is not virtuous,” he said. He also told the newspaper that value for money and modernisation needed to be balanced in order to ready the UK to “fight the wars ahead”.

In June, Healey’s resignation as defence secretary was one of the final nails in the coffin of Keir Starmer’s premiership. The man who now serves as chancellor in Andy Burnham’s government accused Burnham’s predecessor, as well as the former chancellor Rachel Reeves, of putting the country’s security at risk with inadequate funding for the defence investment plan (Dip).

“You have been unable and the Treasury has been unwilling to commit the resources that the nation needs to defend the country at this time of rising threats. I would not be able to accept a Dip settlement that does not give our forces the resources they need. I am now left with no other option than to submit my resignation as your defence secretary,” he wrote.

Announcing his first budget on Wednesday, Healey said he was now fully funding the defence investment plan. He reiterated the target of defence spending reaching 3% of GDP; prompting the Nato secretary general, Mark Rutte, to say the UK was on “a credible path towards meeting the commitment made by all Nato allies in The Hague”. But Healey was criticised for leaving details of his plan to reach that target until next year’s spending review.

Besides spending, Streeting also discussed oversight of service personnel, telling the Times the courts were in the middle of an “active campaign” to “smear the reputation and integrity of our special forces”. He also left the door open to scrutiny of special forces and the UK’s nuclear weapons by MPs and peers on the intelligence and security committee, saying they could be trusted.