Tottenham Hotspur are investigating an alleged incident of racism by one of their own supporters towards South Korean forward Son Heung-min during Sunday’s Premier League defeat by Manchester United.

The north London club confirmed on Monday that they were conducting an internal inquiry after a supporter, James Dickens, said he had confronted another member of the home crowd at Wembley over abuse aimed at Son.

“I’ve not experienced racism at football for about 15 years,” Dickens wrote on Twitter. “But today at @SpursOfficial was hideous. Reported to stewards, confronted him myself.

“Spurs have been in touch and I’ll work with them to find the person,” he wrote. “Stand up to racism and it won’t survive, let it go and it will just get worse.”

Last month, Spurs manager Mauricio Pochettino said he wanted to “kill” bad behaviour and racism from the stands after a fan threw a banana skin on to the pitch during the 4-2 defeat at Arsenal.

Three Chelsea supporters were arrested for racially aggravated public order offences at the League Cup semi-final first leg between Tottenham and Chelsea last Tuesday.

Spurs’ 1-0 defeat to United was Son’s last game with the club this month as he is joining South Korea for their Asian Cup campaign in the United Arab Emirates.