Boris Johnson has said he is “extremely concerned” at the risk of Iran developing a “viable nuclear weapon” after announcing the biggest review of foreign, security and defence policy since the Cold War.

Following his statement to the House of Commons in which he announced the 100 page Integrated Review into UK foreign policy, the Prime Minister was questioned by Liam Fox MP on his assessment of the threat both to British strategic interests and to the Gulf Region posed by the Iranian regime.

Mr Johnson said: “We remain extremely concerned by Iran’s influence in the region, the disruptive behaviour of Iran and particularly, of course, we are concerned about the risk of Iran developing a viable nuclear weapon.”

The PM also spoke of what he described as “an unexpected breakthrough for many in the Foreign Policy establishment” which took place after Israel, the United Arab Emirates and Bahrain signed the Abraham Accords.

The deal was, said Mr Johnson, “a significant and positive step forward.”

Tuesday’s review statement confirmed the UK’s cap on the number of warheads will now increase to 260, having been due to drop to 180 under previous plans from 2010.

Britain will also shift focus towards Indo-Pacific countries, described as the world's "growth engine".

There was a pledge that the UK will do more on the "systemic challenge" of China.

The PM  added the UK would remain "unswervingly committed" to the Nato defence alliance and preserving peace and security in Europe.