Clegg humiliated after Cameron jumps the gun on Trident

The prime minister went out of his way to humiliate Nick Clegg this morning with a robust defence of Britain's nuclear capability which left the Trident review looking redundant even as a face-saving exercise.

The decision to conduct a review into whether there should be a replacement for Trident until 2016 allowed the Tories and Liberal Democrats to enter government together by parking the issue for the whole of 2010 parliament, but the comments from David Cameron suggest its finding will be ignored.

"The highly unpredictable and aggressive regime in North Korea recently conducted its third nuclear test and could already have enough fissile material to produce more than a dozen nuclear weapons," he wrote in the Telegraph.

"Last year North Korea unveiled a long-range ballistic missile which it claims can reach the whole of the United States. If this became a reality it would also affect the whole of Europe, including the UK.

"Can you be certain how that regime, or indeed any other nuclear armed regime, will develop? Can we be sure that it won’t share more of its technology or even its weapons with other countries?

"Does anyone seriously argue that it would be wise for Britain, faced with this evolving threat today, to surrender our deterrent?"

The prime minister insisted the cost of Trident was not prohibitive in a time of austerity, saying it was less than 1.5% of our annual benefits bill.

Cameron will top off the article with a visit to a Scottish defence contractor later today, in a move which will double-up as an event warning of the impact of independence on jobs.

The piece is also a slap in the face for chief secretary to the Treasury Danny Alexander, who was in charge of the review into Trident.

Lib Dem MP Sir Malcolm Brucetold Sky News: "We do accept the case for a nuclear deterrent and we are not in favour of unilateral disarmament.

"We are saying we shouldn't replace Trident on a like-for-like basis but we are looking at alternative nuclear deterrents once Trident has passed its sell-by date."

The Cameron article marks a new Tory confidence in the way the party approaches the Trident question. A few months ago defence secretary Phillip Hammond announced £350 million funding for a new generation of nuclear submarines – a move which already seemed to rule out disarmament or even a change of course from a sea-based deterrent.

That move triggered an angry backlash from Clegg, who accused the defence secretary of "jumping the gun".

He added: "The coalition agreement is crystal clear: it stands, it will not be changed, it will not be undermined, it will not be contradicted. The decision on the Trident replacement will not be taken until 2016, however much other people may not like it that way."

The quotes suggest Clegg will be furious when he reads Cameron's article this morning.

Labour supports a renewal of Britain's nuclear capacity but is open to discussion on "military capability requirements and cost", suggesting there is room for discussion with Liberal Democrats in the event of another hung parliament.

Cameron's move comes amid extraordinary movements in North Korea, which reportedly moves mid-range missiles into position for launch and warning it had authorised plans for a nuclear strike against the US.

Most analysts believe the moves are just sabre-rattling with an eye to later negotiations, but the rhetoric from the capital was nevertheless extraordinary.

"The moment of explosion is approaching fast," the army said in a statement on state news agency KCNA.

"The merciless operation of our revolutionary armed forces in this regard has been finally examined and ratified.

"The US had better ponder over the prevailing grave situation."

War could break out "today or tomorrow", the spokesman for the general staff of the Korean People's Army said.