Boris Johnson's ministerial car was involved in a shunt after a protester blocked the road outside Westminster yesterday.
The demonstrator, protesting about Turkish action against Kurdish rebels, ran into the road outside the gates to Parliament as Mr Johnson left following Prime Minister's Questions.
This forced the lead vehicles in the convoy - a police motorbike and the Prime Minister's Jaguar - to stop, with a support Range Rover running into the back of the luxury saloon carrying Mr Johnson.
The Metropolitan Police said there were no reported injuries and a man had been arrested for offences under Section 5 of the Public Order Act and for obstructing the highway.
The vehicles drove off shortly afterwards in the direction of Downing Street, with a large dent visible on the rear of the Jaguar.
Culture Secretary Oliver Dowden said the Prime Minister was "wholly unscathed and I believe everyone else escaped safely from that situation".
The car was not the only Prime Ministerial transport in the headlines.
Opposition MPs reacted furiously after Downing Street confirmed that work to paint a military plane used by the Prime Minister in the colours of the Union flag would cost almost £1m.
The grey RAF Voyager jet is currently receiving a pre-planned makeover at an airport in Cambridge, with one defence source reportedly saying the new design sounded like something "from Austin Powers".
Confirming the red, white and blue paint job, Downing Street said the work would cost "around £900,000" and would mean that the plane can better represent the UK around the world with "national branding".
Labour shadow minister Emma Hardy said: "For goodness sake. Please can we have a grown-up as a Prime Minister instead of a child."