Police chiefs used to reign like monarchs. Now some seem to last about as long as a Premiership football manager.

The retirement, at just 50, of Scotland’s designated deputy chief constable is, nevertheless, something of a shock.

Iain Livingstone was seen as young enough - and way more than smart enough - to run the national force well in to the 2020s after the current incumbent, Phil Gormley.

Unlike Mr Gormley, and his predecessor, Stephen House, both of whom were schooled at London’s Met, Mr Livingstone was very much a product of Scottish policing. That, and the disarming but somehow authoritative humour that is so often the hallmark of a streetwise Scottish cop, endeared him to the rank and file. When police chiefs retire, their colleagues and staff always make the usual platitudinous statements. In the case of “Livi”, these were sincere.

So how does Scottish policing lose a leader at just 50 and after just 25 years’ service? He only took up his post as designated deputy - the first among equals of Police Scotland’s deputy chief constables or DCCs - last year, replacing Neil Richardson.

Compare this kind of tenure with police chiefs of old.

Sir Stephen House ran Strathclyde and then Police Scotland for the best part of a decade until stepping down, a few months early, amid a media frenzy.

Sir Percy Sillitoe, the man lionised for supposedly beating Clydeside’s razor gangs, was chief constable of Glasgow Police for 11 years from the 1930s to until the war. He only left to become head of MI5. Sir Percy brought in one pertinent reform: retirement after 30 years service. That period has changed over the years, but the theory has always been that officers, especially street officers, have a short shelf life.

Very few police officers now serve out more than 30 years. Even senior officers can spend what to outsiders seems like remarkably short periods in any given post. Mr Gormley and others now have contracts, overseen by the Scottish Police Authority. These deals have time limits. Mr Gormley’s runs out at the end of next year, fuelling speculation of a police clear-out . His deal can be extended. But the days of decade-long police reigns are gone.