The police inquiry into Sir Cliff Richard came under mounting criticism after Dominic Grieve, a former British attorney-general, called its handling of the case "odd" and "very questionable".
Grieve, who left the Cabinet last month, accused the police of colluding with the BBC in a move which led to the search of Richard's home in Berkshire being filmed by the corporation.
Grieve, the most senior politician so far to cast doubt on the police tactics, suggested that the South Yorkshire force might even have been acting in breach of national guidelines in making public its investigation into an allegation that the singer sexually assaulted a boy at a concert almost 30 years ago.
The chorus of criticism grew with complaints by senior lawyers, politicians and fans that Richard was now being kept in a "cruel limbo" while police decide what to do next.
Richard, 73, remained in his villa in the Algarve, Portugal, with his manager, long-time companion and sister offering support. Sources close to the singer said he had yet to be formally asked to return to Britain for a police interview.
South Yorkshire has insisted it is "seeking to speak" to him about the complaint made by his alleged victim more than a year ago. It is thought Richard will eventually be questioned under caution but the sources close to him expressed frustration they remained in the dark about the precise nature of the allegations and how long the inquiry might last.
A police spokesman said: "We cannot give details about the conversations we've had with the person in question. The investigation is ongoing and contact with him will form part of that."
Richard first became aware of the inquiry when he heard reports that his home in Sunningdale, Berkshire, was being raided on Friday while he was in Portugal. The BBC had a news crew stationed at the scene in readiness for detectives arriving and broadcast live footage from an overhead helicopter.
Grieve said yesterday: "I can see that police might not want to warn somebody about a search because they fear a suspect will destroy the evidence. But it was much odder to tip off the BBC that they were carrying out the raid.
"That seems quite extraordinary. I have no reason to think they are acting capriciously, but I think it was odd to notify the BBC so they could have journalists there to film the events.
"Unless the police can show the public sound reason for doing that it suggests a collusive relationship with the BBC which is very odd.
"The BBC's presence is not required. The police have not arrested him or charged him. All they have done is carry out a search of his house so why have they notified the BBC so it could film this operation taking place? I simply don't understand it. It is very questionable."
South Yorkshire Police have admitted they had "worked with" the BBC in advance of the raid on Richard's flat. Jonathan Munro, the BBC's head of news-gathering, has denied that the force was the source of their tip-off.
Nigel Evans, a Conservative MP, who was cleared of sex offences after a trial this year, said Richard would be enduring "torture and torment" after watching his home being raided. He was now left in a situation "worse than limbo".
A spokesman said South Yorkshire Police were contacted some weeks ago by a BBC reporter who made it clear he knew of the existence of an investigation.
"The force was reluctant to co-operate but felt that to do otherwise would risk losing any potential evidence, so in the interests of the investigation it was agreed the reporter would be notified of the date of the house search in return for delaying publication."