Jack Fenwick,Political correspondent and

James Chater

The new Defence Secretary, Dan Jarvis, has said the government must "meet the moment" when it comes to the challenge of increasing defence spending.

Speaking to the Sunday Telegraph, Jarvis, who replaced John Healey on Thursday, said he had a responsibility to ensure the armed forces got the equipment and funding they needed.

He said: "That is the challenge that we have at a point of constrained fiscal resource, and I will be working with my colleagues across Government to make sure that we're in a position to do that."

In his resignation letter, Healey had accused Prime Minister Sir Keir Starmer of failing to provide the money required to "defend the country at a time of rising threats".

Downing Street has said that the government's defence investment plan (DIP) will still be published before the Nato summit next month, but it is not expected in the coming week.

Jarvis, a former army officer, told the Sunday Telegraph he was still working through the detail of that plan, but added that he was "absolutely determined to make sure that we deliver for defence".

He added: "I feel a very strong weight of responsibility to them to make sure that they've got everything they need to do the difficult job that we ask of them. I am utterly determined to make sure that we do that."

Healey's resignation was triggered by an ongoing internal row over funding of the DIP. His departure also triggered the resignation of Al Carns, the armed forces minister.

The plan, which sets out how new military equipment and infrastructure will be paid for over the next decade, was due last autumn but has been repeatedly delayed.

The government has committed to increasing defence spending to 3.5% of GDP by 2035.

Healey suggested that the current defence investment plan proposed increasing defence spending to 2.68% of national income by 2030. He argued that the UK should be hitting 3% by that date.

Healey said the government was only willing to stump an extra £10bn in additional funding, which he described as well short of what was needed.

It is understood the funds available are not likely to change, but that Jarvis will have an opportunity to reassess the spending priorities.

In his response to Healey's resignation, the prime minister said he was "proud of our record on funding", adding the defence funding plan would "provide the resources our military needs to keep us safe".