On a March day this year, a British nuclear-armed submarine quietly returned to its base on the west coast of Scotland after a record-breaking 204 days underwater. HMS Vanguard had 130 crew members on board. They had spent nearly seven months without fresh air or daylight, and with little communication.
Patrols of the UK's nuclear-armed submarines are supposed to last no longer than three months. But the last eight patrols have all exceeded five months, as the navy's ageing fleet of submarines requires ever more time in maintenance. It means the submariners on board are spending longer and longer underwater.
A submariner who was on board one of those long patrols described to me a worrying situation in which the crew ran low on food and medicines. Towards the end of the patrol he described how hungry crew members rummaged for tins of food in hidden compartments inside the submarine. He said they even had to make bread out of custard powder, because they'd run out of flour.
The navy has long found it difficult to recruit sailors into its Submarine Service, often known as the "Silent Service".
But the case of the 204-day patrol by HMS Vanguard raises a wider issue.
Virtually everyone agrees that Britain's armed forces are depleted. Troop numbers are down, morale is weak, and some ageing equipment is in a poor state. And all this comes at a time of greater geopolitical uncertainty, as the threat from Russia looms large across Europe.
Within the next few months, the government will publish its long-awaited Strategic Defence Review – a consultation launched by Sir Keir Starmer shortly after he arrived in Downing Street last summer, designed to identify threats to Britain and recommend how the armed forces can meet them. But there are already doubts over how much it can realistically achieve.
So, as the world becomes more dangerous, what can the government do to reverse the decline – and restore the UK to military readiness?
Dwindling troop numbers
Politicians from all sides, along with military chiefs, admit Britain's armed forces have been "hollowed out". It's true for the Royal Navy and the RAF – and perhaps most acutely, in the British army.
In 2010 the regular Army was nearly 110,000 strong. Now, it is struggling to meet its target of 73,000 soldiers – not enough to fill Cardiff's Principality Stadium.
Earlier this year defence minister and former Royal Marine, Al Carns, told a conference at the Royal United Services Institute, a think tank, that the entire British Army could be "expended" within six to 12 months if it fought a war on a similar scale to the Ukraine conflict.
Last summer the head of the army, General Sir Roly Walker, said the Army needed to be ready to fight a war by 2027 – an admission it isn't ready to fight one in its current state. He said the Army needs to leverage technology, such as drones, new software, and artificial intelligence.
But Justin Crump, an Army Reserve Officer who heads the risk and intelligence company Sibylline, argues that boosts to technology won't make up for the lack of military hardware. "We have big gaps and they're not going to get filled overnight," he says.
The government is also promising to streamline the bureaucratic process of ordering new kit – trying to learn the painful lessons of past mistakes. By the time they eventually arrive, the delivery of hundreds of new Ajax armoured vehicles will have taken more than a decade.
Weaknesses in its Nato commitments
Speak to any government minister about security, they'll no doubt talk about Nato. It's the cornerstone of the UK's security, the government says, and one that has only become more important since Russia's invasion of Ukraine.
According to its Nato commitments, the UK is supposed to be able to field tens of thousands of troops at short notice to defend any Nato territory – with a war-fighting division made up of tanks, artillery, and heavy armour.
But a former senior General told the BBC that in a real war it would run out of ammunition, spares and supplies within weeks or even days. Nor does Britain have much in terms of ground-based air defences – not enough to protect key military bases in the UK, yet alone its towns and cities.
