BBC News viewers “jumped out of their skin” when journalist Matthew Amroliwala accidentally announced that the former prime minister – who died in 2013 – had tweeted about the electoral battle between Joe Biden and Donald Trump.
The tweet had actually come from another former prime minister, Theresa May.
In an interview with former foreign secretary Sir Malcolm Rifkind, Mr Amroliwala said: “Before I ask you the next question let me just put up a tweet that Margaret Thatcher… err has just put out… because…”
Clearly getting a message from the producer in his ear, he quickly corrected himself: “Theresa May, sorry.”
Sir Rifkind, who worked under the late Margaret Thatcher when she was PM, could be seen laughing at the other end of the Zoom call.
The presenter continued professionally as he read out the tweet, which said: “Whoever is elected has an immense responsibility to help tackle our planet’s greatest challenge.”
“That was Theresa May just tweeting there,” Mr Amroliwala continued.
“There are so many challenges, aren’t there, ahead… and I suppose fundamental to that is leadership from the US.”
Viewers said they “jumped out of their skin” when they heard Ms Thatcher was live tweeting the election.
Sir Malcolm later added: “I’ve been around long enough to know that trade negotiations with the United States you do not get any favours.
“Whether you are Boris Johnson, Theresa May or Margaret Thatcher or whomsoever. And that will be true equally with Biden or of Trump. Americans wont give anything without something in return.”