On the day Jeremy Corbyn was elected leader of the Labour party in the UK, his image was retweeted by the US presidential candidate who is enjoying an equally astonishing surge in popularity. Except Donald Trump was being duped.

The business mogul has been tricked once again – with the sweetest of timings – into tweeting a picture of Labour’s new leader, believing it was the father of a fan.

"@HamishP95: @realDonaldTrump My Dad is thinking of voting for the first time ever for you. pic.twitter.com/1u9qi8qUPc" Great. — Donald J. Trump (@realDonaldTrump) September 12, 2015

Corbyn was elected Labour leader by a landslide earlier on Saturday, with Trump retweeting the picture within minutes of the announcement of the veteran leftwinger’s victory.

Donald Trump has RTd an endorsement for Jeremy Corbyn. What is happening. pic.twitter.com/W3Bynz85iI — James Heale (@JAHeale) September 12, 2015

Surely even the most staunch Blairite must acknowledge that Corbyn’s victory was worth it for the Donald Trump tweet. — Tom Phillips (@flashboy) September 12, 2015

It is not the first time, by a long stretch, that Trump has been conned into enthusiastically retweeting pictures of people who are not who they seem.

In July, while in the midst of a row for criticising the Vietnam war record of the 2008 Republican candidate John McCain, Trump retweeted an endorsement from a person he believed to be the son of a Vietnam veteran.

But Twitter users soon pointed out that the uniformed man in the black-and-white picture accompanying the tweet was Jeffrey MacDonald, a convicted murderer who killed his pregnant wife and their two daughters in 1979.

Mr. @realdonaldTrump, that is a photo of Jeffrey MacDonald, a convicted murderer. pic.twitter.com/vG9A57XtVL — Chris Moody (@moody) July 21, 2015

In September last year, Trump was sent a photo of a couple by a Twitter user with the message: “My parents who passed away always said you were a big inspiration. Can you please RT for their memory?”

The picture was of the notorious British serial killers Fred and Rose West.

Hi @realDonaldTrump. My parents who passed away always said you were big inspiration.Can you pls RT for their memory? pic.twitter.com/veBxFNXnOd — Philip Bradbury (@feckhead) September 29, 2014

None of the tweets where Trump has made the error have been deleted since Twitter users pointed out the real identities of the subjects – perhaps suggesting the enthusiastic retweeter is happy to welcome a broad base of supporters.

But his Republican presidential rival Bobby Jindal attempted the dupe once more, with a tongue-in-cheek image of Putin mocking Trump’s knowledge of world leaders.