Army chief Sir Richard Knighton has said the UK is "not as ready as we need to be for the kind of full-scale conflict we might face", as he avoided questions about a reported shortfall in the government's defence spending plans.

Last week, The Times and The Sun reported that the Ministry of Defence believes it will need an additional £28bn to meet its costs over the next four years, prompting a rewrite of the government's defence investment plan.

The plan was due in the autumn of last year but has been delayed.

Speaking to the parliamentary Defence Committee, Sir Richard said he could not provide a date for publication but added that the department was "working flat out" on it.

Following Russia's invasion of Ukraine and the re-election of US President Donald Trump, the UK, along with other Nato countries, has come under pressure to boost its defence spending.

Last year, Labour pledged to increase overall defence spending from 2.3% to 2.5% of national income by 2027, costing an additional £6bn a year. It has also said spending will rise to 3.5% by 2035.

The defence investment plan will set out how new equipment and infrastructure will be paid for and which areas will be prioritised.

According to reports, Chief of the Defence Staff Sir Richard delivered the forecast warning of a £28bn shortfall in spending plans to the prime minister and chancellor ahead of Christmas.

Appearing before the committee on Monday, Sir Richard confirmed he had met Sir Keir Starmer in December and that they had talked about the defence investment plan but added that material discussed was "classified secret".

"I'm not going to talk about that in public," he said.

He added that despite an "unprecedented" increase in spending it was "a statement of the obvious that we can't do everything we want to do as quickly as we want to do it within the context of the budget set".

"That requires ministers to make difficult trade-offs."

The Ministry of Defence has long-struggled to balance its books. The department's analysis in 2023 found that its equipment plan was expected to exceed its budget by £16.9bn and in 2024, the Public Accounts Committee said the UK was facing a £29bn deficit in its spending plans.

During the evidence session, Sir Richard was also asked about the UK's readiness to send troops to Ukraine as part of a European reassurance forces, in the event that a peace deal is agreed.

He did not provide numbers on how many soldiers the UK would send but said he was confident the Army could fulfil its commitment "in the short term".

Asked about the UK's domestic preparedness and national resilience in the event of a conflict, Sir Richard said the UK was not doing "as well as I would want us".

He said there needed to be more work on ensuring infrastructure such as railways and flood defences could be protected against sabotage.

Sir Richard was also pressed on whether the UK would have the capacity to treat increased numbers of wounded soldiers in the event of a conflict.

He said work on the issue was ongoing but added: "We don't have a holistic plan for how we would mobilise the NHS in times of all out war in Europe."