One of the biggest failings of this argument (and there are many failings in it) is that it assumes that the UK has used/is using/will use its (diminishing) power for good around the world.
There are simply too many examples of the UK projecting power for power’s sake, or mostly for profit’s sake, that the argument cannot stand up to scrutiny.
I give you the latest example...
The SNP has called for a public inquiry after it emerged the UK Government allowed British companies to export nerve gas chemicals to Syria.
An investigation by the Sunday Mail newspaper found that two licences were granted to export potassium fluoride and sodium fluoride to Syria in January 2012, almost a year after the start of the country’s bloody civil war.
Both chemicals are ingredients in sarin gas, which was used to kill hundreds of people in the Ghouta area of Damascus in an attack in August.