Veteran singer Sir Cliff Richard will sing with the Royal Air Force 'Squadronaires', one of the UK's finest big bands.
Sir Cliff Richard is preparing to go back on tour as the investigation is anticipated to come to a closeREUTERS

Police have dropped an investigation into one of the sex abuse allegations made against Sir Cliff Richard. Detectives investigating allegations of historic abuse have been unable to uncover any evidence that might substantiate the claims by two men who alleged that the singer assaulted them while making a music video with him in 1981.

The 75-year-old pop star has cooperated with police enquiries, and handed over evidence that demonstrates he was never alone with the men during the production of the music video.

The news that one of the investigations has been dropped was made public by a close friend of Sir Cliff, who has described allegations made against him as 'absurd and untrue'.

The millionaire, who first came to fame in the 60s, has been the focus of a 13 month probe, which began in August last year when the singer was on holiday in Portugal. Police swooped on his £3million Berkshire home as the BBC broadcast live TV images of detectives descending on the singer's property following an allegation of sexual assault on a teenage boy at a Billy Graham Christian rally in 1985.

A confidential police report into the investigation found Sir Cliff Richard was mistreated by police who had tipped off the BBC about the operation before it took place. The singer was not informed of the search and only found out about it by watching BBC News.

Sir Cliff flew back to the UK voluntarily to be questioned by detectives. He vigorously denied all allegations made against him and in February said he had no idea who his accusers were.

"I have never, in my life, assaulted anyone and I remain confident that the truth will prevail," he said. "'I have cooperated fully with the police, and will, of course, continue to do so... the allegations are completely false."

The Sunday Times reports a friend of the star as saying that Sir Cliff was accompanied by a number of minders and staff throughout the event and that some of them have signed affidavits to back his claims that he was never alone. The friend has reportedly claimed that officers have also found inconsistencies in the description given by Sir Cliff's accuser of the Sheffield rally.

The singer is preparing to return to the stage for a month-long tour to celebrate his 75th birthday in October.

Sir Cliff's fans have rallied behind him and concert dates in Birmingham, Liverpool, Manchester and Glasgow sold out within hours. Another date has been added with a performance on London's Royal Albert Hall, where he wraps up with a six-night run, finishing on October 18. Sir Cliff who was recently seen at the funeral of close friend Cilla Black has also been recording a new album in Nashville.