Tom Watson, deputy leader of the British Labour party, said this about outgoing foreign secretary Boris Johnson in an interview on radio station LBC:
[Boris Johnson is] the only politician in UK history that posed for a photograph while signing his own resignation letter.
(the context of the remark is Watson criticising the resignation, characterising it as a vainglorious stunt intended to boost his leadership ambitions - the claim that he's the only British politician in history to do this is used to support the idea that it goes beyond typical political antics)
There seems to be no doubt that Boris Johnson did take time out of his schedule (seemingly, at a time when he was expected to be hosting a summit of East European ministers) to organise a photoshoot and pose for photographs signing his own resignation letter. Tabloid The Sun (edited by a jogging partner of Boris Johnson, therefore likely to be an informed and sympathetic source) credits the photos to professional photographer Andrew Parsons, and includes multiple poses from different angles in a gallery, describing the photoshoot:
Boris - who's been replaced by Jeremy Hunt - hired photographer Andrew Parsons, who used to work for David Cameron, to capture the moment he formally resigned.
Is it true that this is the first time a British politician has arranged for a photographer to photograph the signing of their own resignation?