By Chris Summers
BBC News Online
As part of BBC News Online's investigation into Secret Britain, we spoke to an alleged victim of unjustified phone tapping.
Malcolm Kennedy began suspecting his telephone was tapped shortly after he set up a new business in 1998.
It may sound like paranoia but he is not alone in believing his phone is tapped.
Many, like Kennedy - who has long protested about a manslaughter conviction - have had high-profile disputes with the police or other public institutions.
Kennedy believes MI5, the Special Branch, a department of the Metropolitan Police or someone else is sabotaging his phones to keep tabs on him and interfere with his business.
Malcolm Kennedy believes his phones have been tapped
The pressure group Privacy International receives at least a dozen calls a week from people who believe their phones are tapped and they say this is the tip of the iceberg.
What is more it is virtually impossible for them to confirm officially whether or not their phones are tapped.
The police and security services, if approached directly, have no obligation to confirm or deny they are tapping a phone and critics say the Investigatory Powers Tribunal - which oversee complaints - is toothless.
Life and trials of Malcolm Kennedy
23 Dec 1990: Patrick Quinn beaten to death in a cell at Hammersmith police station
12 Sep 1991: Malcolm Kennedy convicted of Quinn's murder
1993: Kennedy freed on appeal pending a retrial
1994: Kennedy convicted of manslaughter and jailed for nine years
1996: Kennedy leaves jail, having served half his sentence.
Jan 2003: Investigatory Powers Tribunal begins hearing Kennedy's complaint about phone tapping
It has never upheld a complaint made to it. Likewise, its predecessor, the Interception of Communications Tribunal, did not uphold a single complaint in its 13 years of existence.
In the early and mid-1990s Kennedy's case was something of a cause celebre among critics of the criminal justice system.
The former restaurateur from Hackney, east London, who had no previous criminal record, was convicted of murdering Patrick Quinn, 56, in a cell at Hammersmith police station where both had been detained for drunkenness.
He maintained his innocence and told his trial he believed Quinn was killed by police officers.
Kennedy's murder conviction was later quashed but he was convicted of manslaughter at his retrial.
After his release from prison in 1996, Kennedy tried to rebuild his life while still seeking evidence which might clear his name.
Before his conviction he had been a successful restaurateur but he lost everything when he went to jail, and when he came out he found it almost impossible to get a job because of his conviction.
Kennedy decided the only option was to work for himself and he set up a "man and a van" business, offering small-scale removals.
Kennedy has always denied killing Patrick Quinn
He advertised in both the Yellow Pages and on the internet but received constant reports that people were having trouble getting through to his numbers.
Kennedy was told by some customers and friends that his phone number was giving an engaged or dead signal.
He himself occasionally heard strange sounds while he was talking on the line and at one point heard a previous conversation being played back over the phone.
He also said that on occasion he overheard someone whispering things like: "That's Kennedy - I recognise his voice".
He checked with his phone company and was told there was nothing wrong with his line.
Kennedy, now 56, complained to then Home Secretary Jack Straw, the Commissioner of the Metropolitan Police and the Interception of Communications Tribunal.
He has since taken his case to the Investigatory Powers Tribunal, which was set up under the Regulation of Investigatory Powers Act 2000.
The civil rights group Liberty is acting for Kennedy in a challenge to the rules under which the tribunal will hear his complaint.
In January 2003 the Guardian newspaper won the right to have legal arguments relating to Kennedy's case heard in public as long as they are not about anything secret.
Kennedy is still waiting for his complaint to be heard by the tribunal.
He says he has spoken to many miscarriage of justice campaigners who have suffered similar problems with their phones.
"They tend to work around it, but I feel so outraged that they should do it at all that I pursue the matter. It's affecting my economic wellbeing," said Kennedy.
He said: "People assume you're paranoid. They think I'm potty. It (phone tapping) does send some people into mental illness."
Solicitor Tony Murphy, who dealt with his complaint to the Met, said: "The situation in which Malcolm Kennedy finds himself is nothing short of Kafkaesque.
"The current system appears not to allow for the possibility that the police or security services can act improperly in intercepting communications."
A Metropolitan Police spokeswoman said she could not comment on Kennedy's case but added that, if his phones had been tapped, it would have been in accordance with the guidelines drawn up by the Association of Chief Police Officers (ACPO).
An ACPO spokesman said those guidelines were not available to the public.
"They are operational, for viewing by police officers only," he said.