A photo which appears to show Prime Minister Boris Johnson without a mask on public transport has gone viral.

The undated photograph of Boris Johnson, who appears to not be wearing his mask properly on a South Eastern train, was published by The Spectator.

A closer look at the image shows Boris Johnson's mask underneath his chin while a bag that resembles Gregg's branding can be seen nearby.

The image has sparked a mixture of outrage and interrogation on social media - does it show Boris Johnson ignoring his own Government's guidance or is he eating?

The source, date and time of the photo is currently unknown - though the Spectator article claims it was taken "yesterday" (December 16, 2021).

Since November 30, Government rules once again made it mandatory to wear face masks on board trains and in all enclosed areas of railway stations.

Masks are mandatory from the moment you enter a station, your journey and exiting the station at the other end.

If you are eating or drinking, you are allowed to take your mask off on public transport.

In the Spectator's article, gossip columnist Steerpike said: "Closer inspection reveals that Boris Johnson is in fact wearing a mask under his chins, the sort of sloppy face-not-covering that could have us common citizens fined or even arrested if we dared to do the same."

But the photo has divided public opinion with some believing the photo shows Boris Johnson eating a Greggs meal.

The outrage falls against the backdrop of several reports of Christmas parties at the height of December 2020's coronavirus restrictions.

It has been a week peppered with woes for the Prime Minister – starting with a major rebellion in the Commons over Covid-19 measures, and ending with a stinging defeat in a by-election for what has traditionally been a safe Tory seat.

The Conservative Party leader also faces allegations that he misled his ethics adviser over what he knew about a controversial refurbishment of his No 11 flat.

Meanwhile top Conservative and former mayoral candidate Shaun Bailey quit his role after the Daily Mirror published an image showing 24 people crowded together at a Christmas party.

The event took place at the Conservative Party’s headquarters on December 14, when London was restricted under Tier 2.