Donald Trump has made an unfortunate blunder while campaigning on the eve of New York’s high-stakes primary by getting the date of the World Trade Center attacks wrong.

During a speech in Buffalo, a slip of the tongue meant he referred to the September 11 atrocity as “7-Eleven”, which is in fact the name of a popular chain of convenience stores.

Failing to correct himself after the gaffe, the Republican front runner said: “It’s very close to my heart because I was down there, and I watched our police and our firemen down at 7/11, down at the World Trade Center right after it came down, and I saw the greatest people I’ve ever seen in action.”

The mistake could prove embarrassing for Mr Trump as he has repeatedly mentioned the terror attacks while campaigning across New York, his home state.