Amir Khan has revealed that prime minister David Cameron is a "good friend" and previously helped him with visa troubles.

The 28-year-old was refused the paperwork to travel to the United States on September 11 last year to commentate on the bout between Floyd Mayweather Jr and Marcos Maidana.

However, after a quick call to the Conservative Party leader, the Bolton-born boxer was given the go-ahead to travel.

"I was flying out on September 11," Khan told Times Weekend. "I think that the American immigration guys get edgy. They just told me my visa was refused and I couldn't get on the plane.

"David Cameron takes my calls. He is a good friend. I rang him and said I had a bit of a problem. He said, 'hold on a minute' and then he called me back and it was sorted."

Khan recently visited the military-run school in Peshawar, Pakistan where 132 children were killed by Taliban gunmen.