Stephen Kerr, who was elected MP for Stirling at the snap general election last June, tweeted a photo of several unknown protestors outside his office.
They had hung a banner that read ‘Tory Scum Out’ at the MP’s office, although whether their protest had a wider meaning hasn’t been established.
Mr Kerr, who gained the seat with a majority of just 148, accused the group of representing ‘extremist nationalist politics’.
He tweeted: “Scene at my office earlier today and the face of extremist nationalist politics in Scotland in 2018. Frankly insulting to the 18,291 people who voted @ScotTories in Stirling last June.”
Some backed the MP after his tweet, though others defended the men’s right to protest, and criticised Mr Kerr for his apparent assumption that the men were nationalists.
A spokesman for the Scottish Conservatives said: “This was a disgraceful episode, and the people involved should be ashamed of their conduct.
“Quite what they were trying to achieve is a mystery.
“They have only succeeded in insulting thousands of voters who elected Stephen, and probably damaging whatever cause they profess to represent.”