Cliff Richard pulls out of charity event after sex assault allegations

Cliff Richard has cancelled his appearance at a charity event after his home was searched as part of an investigation into an alleged sexual assault.

Singer Cliff Richard says allegations of sexual impropriety against him are "completely false". (AAP)

The veteran singer was due to appear at Canterbury Cathedral next month but his spokesman says he doesn't want the event to be overshadowed by the allegation.

Police searched Richard's apartment last week over the alleged assault on a young boy at a religious event in 1985.

Sir Cliff has firmly denied any wrongdoing.