A police investigation into sexual abuse claims against Sir Edward Heath is to be concluded in the coming weeks.

The inquiry, dubbed Operation Conifer, is set to be closed soon, but the findings will remain confidential.

One source told The Sunday Telegraph that private detectives who were hired to aid the investigation are not having their contracts renewed.

Operation Conifer, the investigation into sexual abuse claims against Sir Edward Heath, is to be wound down in the coming weeks

The investigation was launched in August 2015 and has been undertaken by Wiltshire Police. Above is Sir Heath's former home

They said: 'The inquiry is coming to an end. The contracts are up and have not been renewed even though there was an option to do that.'

Friends of the former PM, who died in 2005 aged 89, have insisted the inquiry has found no evidence to implicate the politician as the questions asked were 'lacking in detail', according to the newspaper.

Lord Armstrong, the former Cabinet secretary and Sir Edward's principal private secretary from 1970 to 1974, said: 'They have interviewed former staff at No 10 and asked them if they were ever aware of young men slipping in and out of 10 Downing Street. It's absurd. You couldn't slip in or out. There was a door with a policeman on it.'

The £1 million investigation has been subject to criticism since being launched in August two years ago, with many people saying it was a waste of tax payer's money.

Sir Edward's godson, Lincoln Seligman, previously slammed the amount that was spent to conduct the enquiry.

He said: 'Nearly two years and a million pounds, and all we have from the Chief Constable are nudges and hints, and the occasional declaration that he's convinced of Edward Heath's guilt. And complete silence from the Wiltshire Police Commissioner.

'We need a judge like Sir Richard Henriques to look into the way this inquiry is being run. Urgently.'

Following reports of criticism of the case, Chief Constable for Wiltshire Police Mike Veale penned a 1,600 word open letter defending the investigation and published it online in December.

Sir Edward's godson, Lincoln Seligman, previously slammed the amount of money that was spent to conduct the enquiry

In the letter, Mr Veale said that when he took on this investigation he knew it would 'attract intense scrutiny', however he said he was 'very concerned and profoundly disappointed' about the speculations that had been made, and the 'impact' that this could have on the 'the public's confidence in the police'.

He added: 'This is not a 'fishing trip' or 'witch-hunt' – both of these terms have been unfairly levelled at us. The legal role of the police service is to, on behalf of the public, impartially investigate allegations without fear or favour, and go where the evidence takes us.

'Critically, it is not the role of the police to judge the guilt or innocence of people in our Criminal Justice System.'

A spokesman for Wiltshire Police said of the final report: 'Our approach to public confidence is to be as open and transparent as possible, and at the conclusion of the police investigation, the force will take advice as to what we can legally put in to the public domain.'