A retreat from controversial conflicts such as Iraq and Afghanistan, a relatively buoyant economy and young people increasingly unwilling or unready to enlist are amongst the reasons why the British army suffers from shortfalls in numbers of as much as 20% or even 30% in some infantry regiments.

It is a problem that reflects poorly on those running the army – where shortfalls are greater than in the navy and air force – and on Conservative ministers representing a party that traditionally considers itself the custodian of Britain’s security. But the critical question is to what extent army size matters in the early 21st century.

The reality is a limited political appetite for serious engagement by ground forces. Scarred by the memory of Iraq, MPs are unlikely to vote for intervention in countries far from home; without an ongoing campaign to get involved with, potential recruits may decide there are better careers to follow.

It is a decade since combat operations ended in Iraq and five since they ceased in Afghanistan, and while there are several important peacekeeping missions, such as the recently announced plans to assist the UN mission in Mali, they only occupy a smaller number of troops. In the case of Mali for instance, just 250.

The area of greatest tension at present is the Gulf, where Britain has become embroiled in a tit-for-tat of tanker seizures with Iran. Protecting oil suppliers is strategic for the UK – as well as other western nations – but this is a task for the Royal Navy.

Meanwhile, the pool of potential recruits is diminishing. The unemployment rate among 16 to 24-year-olds is at half the level it was between 2011 and 2013, when it touched 22%. That figure is now 11.4%.

Posters from a 2019 British Army recruitment campaign. Photograph: MoD/Crown copyright/PA

The country already has a problem with obesity, putting off potential recruits. Recent figures even indicated that one in 10 serving soldiers were clinically obese.

Weary recruiters complain that others fail the grade because they have tattoos on their face or the palms of their hands.

There are also so many stories or mental health problems faced by veterans – never mind the physical risk of injury in conflict – that the alternative of further education makes the option of serving less attractive.

It is not well publicised, but the armed forces have quietly been squeezed of resources under various Conservative governments as funding has been focused on the NHS and to a lesser extent schools. While Jeremy Hunt said he wanted to boost defence spending from 2.1% to 2.5% of GDP, Boris Johnson, the prime minister, has made no such commitment.

Still, there is no shortage of security experts who talk up the threat from Vladimir Putin’s Russia. But even allowing for the seizure of Crimea in 2014 – it is hard to believe there is a likely prospect of further invasions in eastern Europe. The real issue is countering Russian disinformation and electronic warfare.

Britain’s generals recognise some of this, with the army announcing a reorganisation at the beginning of this month, aimed at giving a clearer focus to its own propagandists and hackers by housing them in one of its three divisions. The army even advertised for “snowflakes” and “binge gamers” and “selfie addicts” at the beginning of the year in a recruitment campaign that led to a doubling of applications in January, although it was not clear if it could be sustained.

Which means the real question is whether the army can (or is the right place to) make the transition from armed fighters to keyboard warriors.