Reports that demonstrators rallied outside the house of Labour MP Stella Creasy were, it transpires, untrue.

She has issued a statement via her Facebook page in which she wrote: “For avoidance of doubt, I have no reason to believe Tuesday’s protest in Walthamstow went past my house.”

Stories took off following a Facebook posting in which a man who identified himself as Paul S Jakubovic wrote: “Outside Labour MP Stella Creasy’s house in Walthamstow tonight”.

His claim was widely reported on social media and several mainstream outlets that anti-war marchers had gathered outside Creasy’s home. They included the Independent and the Huffington Post, and by broadcasters, including the BBC and LBC.

The Facebook claim, since deleted, also included a photograph. It was falsely said to picture people outside Creasy’s home. In fact, it showed people gathered outside a mosque prior to marching to Creasy’s Walthamstow office.

Labour MP Diane Abbott took the claims seriously enough to tweet sympathetically: “Protesting outside someone’s home is a step too far.”

Tom Watson is trying to intimidate us, say anti-war protesters Read more

One of the protest organisers, Sue Wheat, wrote in seeking “to set the record straight” that the inaccurate Jakubovic posting “started off a mass media misinformation story about constituents bullying Stella.”

Creasy, who voted for air strikes on Isis in Syria, backed up Wheat’s version of events that night. She wrote: “I have no reason to think those who took part on Tuesday were not peaceful in their conduct.”

She went on to say that she has since received hundreds of “violent and abusive” online messages.

But the lesson from this sad business is that mainstream media outlets should be checking single-sourced social media claims before rushing into print or to the microphone.

The non-story took off and got legs of its own. And who, anyway, is Paul S Jakubovic? Does he exist? Or did someone take his name in vain?

Whatever the case, a single posting using his identity cannot be said to be a credible journalistic source.