Khan who is a former Olympics silver medalist was ahead on points over MacCloskey when the ring physician ruled McCloskey could not continue fighting due to a bad cut in the head caused by an accidental head butt in the sixth round.
The referee took the advise of the ring physician and decided to stop the fight.
There was widespread booing from many in the 16,000 MEN Arena crowd, while McCloskey's manager Barry Hearn condemned the decision as "unprofessional" and said he would lodge a complaint with the British Boxing Board of Control, Reuters reports.
“That’s the worst stoppage I have ever seen in 25 years in boxing. It’s a little nick,” said Hearn
. “Boxing is in enough of a mess as it is and this just makes a mockery of another high profile contest.”
Despite the complains from McCloskey's handlers, Khan said he knew he would have knocked down McCloskey if the fight continued.
"He didn't win one round," he said. "I was hurting him, I wasn't tired, and I promise you if it had gone two more rounds he would have been knocked out. There is no point in a rematch."
"He was very tricky, his head was low but I caught him with a clean shot in the fifth round and his legs went so any minute he was going to go," he told the BBC.
Amir Khan was born in Bolton, England. His grandparents were originally from Pakistan but emigrated to Britain in the 50's.
Khan, who was born on December 8, 1986, is the current WBA light welterweight champion. He just defended his title against Marcos Maidana last December 11 in Las Vegas, Nevada.
McCloskey, who was born in Northern Ireland in 1979 is undefeated in 22 fights. His loss to Amir Khan is his first in his professional boxing career.
With his unanimous win over McCloskey, Khan's professional boxing record now stands at 25-24-1.