CASD stands for Continuous At Sea Deterrent. This defence strategy is executed for Britain by the Royal Navy’s four nuclear-powered, ballistic missile-armed submarines, SSBNs.
But the CASD is now at severe risk of no longer being continuous.
When HMS Resolution, the first of the bombers as the Navy calls them, went to sea in 1966, she and her sister boats’ patrols were limited to 60 days. Circling at three knots for weeks on end is the most boring form of seagoing the Navy has ever had to endure. OK, they have a gym on board, watch films and play games, as well as regularly carrying out drills and exercises to keep the crew on the ball in case the signal to launch is received. Letters from home? Forget it. Very brief, carefully vetted messages from and to wives and other loved ones are permitted occasionally. Women also serve in the bombers, a women’s lib capitulation that the late Lord Boyce, Chief of the Defence Staff, fought hard to prevent.
Now CASD patrols have increased in length to almost seven months. As many as 204 days have been endured recently. Even with unlimited fuel for propulsion from small modular reactors (lesson here, Mr Miliband?) and power to distill fresh water, fresh food carried on board is soon exhausted and replaced by tinned and frozen. Locking up young men and women in a steel tube for more than 200 days has led to many serious problems which should surprise no one. Nor should it be a surprise that crew members in submarines have been caught using hard drugs including cocaine, cannabis and ecstasy.
If the CASD does collapse, we can be certain that Russia will know immediately. They will have had, from the very beginning, a spy with binoculars in a house across the Gareloch, Faslane, where all our submarines are based, monitoring the comings and goings of the SSBNs, although this system may now have been replaced by satellites. The moment they see one returning without having seen her relief boat previously departing they will know that there isn’t one at sea.
The government needs to do three things urgently to prevent this disaster from happening.
First, vastly increase the defence budget allocation to the royal dockyards and civilian repair yards to enable them more rapidly to complete submarine refits and routine maintenance. This would need to include higher pay for all staff, possibly with other incentives such as bonuses, and apprentice schemes. The recent revelation that one of our destroyers has spent the last nine years in refit reveals the inadequate state of naval repair facilities.
Second, significantly increase submarine pay for naval personnel to a) demonstrate how much their dedication and sacrifice of quality of life are appreciated and b) help to reduce wastage of highly trained personnel who leave the service because of the excessive demands on them.
Third, immediately start a new-build programme so that the present ageing four bombers can be retired before their patrols become ever longer and their maintenance periods and refits become ever longer too.
Tragically, we all know that none of these three things is going to happen. Starmer has stated that the defence budget will be increased when the situation allows it, i.e. never. The Defence Investment Plan (DIP) was supposed to be published last October but it still hasn’t seen the light of day. This is because the money for the investment proposed in the Strategic Defence Review published on July 8, 2025, just isn’t there.
So President Trump is quite justified in criticising our inadequate contribution to Nato.
Editor’s note: David served in the Royal Navy for 12 years from 1959 to 1971 during which time he was the engineer officer of two diesel electric submarines. The ballistic missile submarines were commissioned during this time and his second boat was based at Faslane the same as the bombers.
