The Armed Forces are preparing for a potential war with North Korea, sources have revealed.

Officials have been instructed to draw up plans for how Britain would respond if war broke out with Pyongyang amid heightening tensions between the West and dictator Kim Jong-Un.

One option involves deploying Britain’s new aircraft carrier – due to be handed over to the Navy later this year – to the region before she has undergone flight trials.

Details of the secret operation plan have emerged after Donald Trump warned that ‘only one thing will work’ when it comes to dealing with North Korea, which has continued nuclear and rocket tests despite widespread condemnation.

North Korean leader Kim Jong Un inspecting military plans with his generals

The US President said that, over 25 years, talking with North Korea ‘hasn’t worked, agreements violated before the ink was dry, makings fools of US negotiators’.

In return Kim said his nuclear weapons were a ‘powerful deterrent’ that guaranteed North Korea’s sovereignty.

The UK’s contingency plans have been mapped out in recent months amid fears these tensions could escalate into war.

Under one scenario, HMS Queen Elizabeth, along with 12 F-35B fighter jets, would be brought into service early to join US warships off the Korean peninsula.

The 65,000-ton carrier, which has a 700-strong crew, could be escorted by Type-45 destroyers and Type-23 frigates.

A senior Whitehall source said: ‘We have plenty of ships to send… the Type-45 destroyers, the Type-23 frigates. Britain’s new aircraft carrier could be pressed into service early if things turn south.’

Under one scenario, HMS Queen Elizabeth, pictured, along with 12 F-35B fighter jets, would be brought into service early to join US warships off the Korean peninsula

Ministers had refused to say whether the UK had a plan should conflict erupt with Pyongyang. But military planners are examining options including tactics similar to those used to defend the Falklands.

In 1982, aircraft carrier HMS Illustrious was rushed into service early for the war with Argentina.

HMS Queen Elizabeth is not due to enter service until 2020, but she will be commissioned at the end of this year. Navy sources said she could technically then be sent to war. While Kim’s threats have focused on the US, British officials fear the UK would be dragged into any war with the regime, which has been sanctioned by the UN.

Last week Defence Secretary Sir Michael Fallon told the Tory Party conference: ‘North Korea’s illegal testing underlines just how irresponsible it would be to scrap the deterrent that protects us.

‘It is all very well Jeremy Corbyn saying he would never use nuclear weapons but Manchester and London are closer to Pyongyang than Los Angeles.’

Sir Michael Fallon has said North Korea's missile testing 'underlines just how irresponsible it would be to scrap the deterrent that protects us'

He also said the public should not be ‘squeamish’ about sending soldiers to fight in foreign countries again, despite the loss of life in Iraq and Afghanistan.

Sir Michael said this meant deploying ships, planes and even troops on the ground if asked for help.

Ahead of next month’s Budget, he called for more cash for defence, warning that threats to Britain had intensified.

HMS Queen Elizabeth is conducting sea trials in Portsmouth. She will then carry out tests on mission systems before being handed over to the Navy.

After that date, the ship will carry out more tests, including trials with stealth fighter jets.

A Navy source said: ‘In the Falklands we had to react to an event and HMS Illustrious was accelerated to respond. This was a reaction to protect British territory, however. In this case [North Korea], the UK would be part of a united global coalition. We would see what support we could give.’ As well as missiles, North Korea has also tested a hydrogen bomb – a far more devastating weapon than conventional atomic bombs.