In a report for the Policy Exchange thinktank, Sir Jock Stirrup, ex-chief of the Defence Staff, said Britain’s reliance on an “outdated nuclear doctrine” is insufficient, and deterrence requires a spectrum of conventional and nuclear capabilities. The report recommends resuming large-scale military exercises, including nuclear elements, to signal a credible threat to Russia, China, and other adversaries.
The warning comes as Labour leader Sir Keir Starmer announced that the UK could deploy peacekeeping troops to Ukraine alongside France if a ceasefire is agreed. Reports suggest the UK contingent could be as few as 7,500 troops, though Sir Richard Shirreff, former NATO deputy commander in Europe, and ex-defence secretary Gavin Williamson have argued that at least 50,000 would be needed to deter Russia effectively.
The international situation has been further complicated by the US-UK seizure of the Russian-flagged oil tanker Bella 1, linked to Venezuela, for violating US sanctions.
Sir Jock and co-author Daniel Skeffington said Western powers failed to deter Russian aggression in Ukraine because they did not demonstrate credible military capabilities. “Deterrence works as a package,” they wrote, noting that reliance solely on submarine-based nuclear weapons is insufficient.
The report also warned that the UK’s expertise in nuclear strategy has declined since the Cold War, creating gaps exploited by adversaries. With rising tensions and China’s nuclear expansion, Stirrup called for renewed investment in defence and active demonstration of capability and resolve.
Meanwhile, Sir Keir has proposed increasing UK defence spending to 3.5% of GDP and urged European allies to follow suit, amid growing concerns over reliance on the US and questions over the UK and France’s capacity to guarantee peace in Ukraine.
