The witness protection programme is designed to keep safe the most vulnerable court witnesses - but how effective is it? Radio 4's File on 4 speaks to people who entered the programme.
"I heard footsteps coming up the stairs. My back was to the door, and I turned around and two big blokes came through the door in balaclavas, asked me my name, I said 'yeah' and they pulled out a gun and stuck it in my mouth."
Chris - not his real name - used to run a successful business in the north-west of England, in partnership with someone he regarded as a friend.
However, it turned out this friend owed a lot of money to a criminal gang and they wanted it back in any way they could get it.
"They said they wanted £100,000 - I had no dealings with these people at all, so couldn't understand why," Chris recalls.
"They smashed my teeth with the gun, and every time I put my hand up to stop them they told me to put my hands down so I wasn't allowed to protect myself - and if I did the beating got worse, so in the end I just got physically beaten."
Chris was too scared to seek hospital treatment, but he went to the police to ask for protection. He made a statement and agreed to be a witness - but that only made the gang more determined.
What followed was a relentless campaign of intimidation against Chris - the gang also threatened his close friends, who had shots fired at their homes as well as attempts to burn down their houses.
"The violence was nothing to do with the money in the end, it was to do with getting me to drop the charges," says Chris.
The police 'lied'
For two months the police helped Chris and his wife to go into hiding. They were living in temporary accommodation while police conducted investigations.
Eventually, it was decided Chris and his wife were in so much danger, they were asked to consider becoming protected persons - a term which has legal status and places a duty on police to protect their safety.
Once in witness protection, police will try as best they can to create an equivalent lifestyle for the people they are helping.
Chris says that based on assurances he was given in the run-up to the trial at which he was to appear as a witness, he thought this would happen.
"Every time I asked [the police] a question regarding my business, my home or anything like that, every single answer was exactly the same - 'don't worry, everything will be taken care of'."
"They just kept saying 'keep your head straight for the trial and we'll discuss it further after the trail'."
Today, Chris says everything was not taken care of, and once in hiding he was not allowed to work, either - this meant he could not keep up with his mortgage payments.
Furthermore, Chris could not call his bank to explain the situation without breaking cover - and eventually he lost his home and business. Chris and his wife now live on around £100 a week given to them by the police - previously, he says, he was earning around £150,000 ($239,000) a year.
Chris says the only reason he agreed to give evidence was because the police told him his personal life would be taken care of.
"They mis-sold me," he now claims. "They tell you everything will be taken care of. Well, it's not, so they lied. They lied to me.
"The government, the police, have lied in order for me to give evidence. They don't care about me, they care about a conviction."
New protection scheme
The Association of Chief Police Officers (Acpo) says that does not happen, and that people do get help, but Chris is not the only one with concerns about the level of support on offer, once a trial is over.
The BBC's File on 4 programme found other cases in which witnesses said the terms of their protection were unfavourable - but if they do not sign the agreement, they cannot be fully protected.
"One of the many reasons why protected persons are in a uniquely vulnerable position is that they are not permitted copies of these agreements," says Fiona Murphy, a solicitor who has acted for some of those in witness protection who have broken cover looking for help from lawyers.
"They're not entitled or able to seek legal advice with regard to the content."
Assistant Chief Constable Andy Cooke, who speaks for Acpo on witness protection, concedes there needs to be some kind of independent mediation in cases where disputes arise.
"I would be quite amenable to having an outside system of reviewing individual cases to ensure they were fair. It doesn't happen at the moment [but] its certainly something that we're considering," he says.
Hopes for that rest with a plan to create a new nationwide service for protection when the National Crime Agency comes into being, scheduled for next year.
In the meantime, Ms Murphy says her firm is regularly approached by people desperate for help, who feel trapped in a system they regard as unfair.
"We receive quite a significant number of telephone calls from protected persons seeking legal advice, they tell pitiful tales of lives absolutely destroyed.
"It's not always the case that we can help... and it's certainly our impression that there's a great number of aggrieved individuals out there who are without access to legal advice and are deeply aggrieved with regard to the circumstances in which they find themselves."
The police service knows it is important to get this right at a time when it is trying to encourage more people to come forward to give evidence against serious and organised crime - and witness testimony is often vital in such cases.
Witness intelligence leaked
Sarah, originally from south London, had a close friend murdered by a gang, many of whom were known to her.
She was too frightened to go to court, but says she agreed to help police with intelligence gathering on condition of anonymity.
"Every single communication we had, I stressed this was not something which could come out, that it couldn't come from me, and I would be assured it was strictly to help police in their investigation."
Suspects were subsequently arrested, but a few days before the trial she was sent a warning.
"I got call from a friend asking if I had been feeding information to police… he said £3,000 was being offered to stop me going to court."
The next day police confessed that Sarah's intelligence material and personal details had been handed over in error to the defence teams in a process known as disclosure.
"These were people who I was bumping into regularly... some were still at large.
"I was actually petrified, and for the safety of my family at that point."
After the mishandling of her details by the criminal justice system, the Metropolitan Police offered to put Sarah into witness protection, but she could not bear the thought of being separated from her family so she declined.
Instead she moved away from the area she lived in and changed her name, hoping the gang would not come looking for her.
Sarah is planning to issue legal proceedings against the Met for their part in the failure to protect her identity.
The force declined to comment on the case.
For Acpo, ACC Cooke says part of people's dissatisfaction with the witness protection programme is because they struggle to adjust to new life circumstances.
"It's totally different from anything they've been used to before, it's an absolutely new life, they're having to learn new skills, so some people will never be happy.
"We as a police service have got to understand that, and we've got to make sure that we can do all we can to make this transition as simple as possible."
He said what was important was that "individuals involved in this side of business understand the levels of stress and confusion that's going on for those on schemes like these".
ACC Cooke says the police do their very best to help people in life-threatening circumstances, but he says improving the service by moving to a national system should make it better for people to give evidence.
"I think if we can make the system more attractive, I think more people will be happy to come forward… in the circumstances knowing firstly that we can protect them and secondly that they won't get a raw deal."
Listen to the full report on File on 4 on BBC Radio 4 on Tuesday 27 March at 20:00 BST and Sunday 1 April at 17:00 BST.