Boris Johnson is set to get caught up in a new arms race by increasing the number of Trident warheads aboard the nuclear submarines sailing from the Clyde.

The Prime Minister is to commit the UK to increase the number of warheads from 180 to 260, according to leaked reports of the much-vaunted review of security, defence and foreign policy after Brexit.

The £10 billion rearmament in response to perceived threats from Russia and China would end three decades of gradual nuclear disarmament and it has outraged the SNP and disarmament campaigners.

SNP defence spokesman Stewart McDonald said he was astonished by the outdated defence policy being included in a review of Britain’s place in the world post-Brexit.

McDonald said: “For the prime minister to stand up and champion the international rules-based system before announcing in the same breath that the UK plans to violate its commitments to the international treaty on non-proliferation beggars belief.

"Renewing Trident nuclear weapons was already a shameful and regressive decision, however, increasing the cap on the number of Trident weapons the UK can stockpile by more than 40% is nothing short of abhorrent.

"It speaks volumes of the Tory government's spending priorities that it is intent on increasing its collection of weapons of mass destruction - which will sit and gather dust unless the UK has plans to indiscriminately wipe out entire populations - rather than address the serious challenges and inequalities in our society that have been further exposed by the pandemic."

Kate Hudson, the general secretary of the Campaign for Nuclear Disarmament, said: “With the government strapped for cash, we don’t need grandiose, money-wasting spending on weapons of mass destruction.”

Britain has far fewer warheads stockpiled than Russia, estimated to have 4,300, the US on 3,800 or China, which has about 320. But each warhead the UK holds is estimated to have an explosive power of 100 kilotons.

The atomic bomb dropped on Hiroshima at the end of the second world war was about 15 kilotons.

Elsewhere the review is said to warn there is a “realistic possibility” that a terrorist group will launch a successful chemical, biological, radiological or nuclear attack by 2030.

The Prime Minister will set out the findings of the year-long survey, billed as the most radical reassessment of Britain’s place in the world since the end of the Cold War, in the Commons later today.

The 100-page document argues for an “Indo-Pacific tilt” away from the European Union in which the UK deepens defence, diplomatic and trade relations with India, Japan, South Korea and Australia in opposition to China.

This will, according to the report, mean investing in cyber warfare capabilities and deploying the new Queen Elizabeth aircraft carrier, built in Rosyth, to the Pacific theatre later this year to send a bullish message to Beijing.

The review is also expected to include the creation of a new state-of-the-art counter-terrorism operations centre to streamline the response of police and the intelligence agencies in the event of an attack.