Police have been left in an "unbelievable nightmare" fearing a landmark court judgement could force them to allow suspected criminal to go free.

A ruling this week means conditions imposed on police suspects could be unenforceable.

Suspects, released to await decisions on whether they will be charged, can no longer be detained for contacting witnesses or victims, breaking night-time curfews or failing to turn up at police stations at appointed times.

The changes came after the system police used for 25 years was ruled illegal by a judge.

Sussex Police officers, who were left working overtime to try to find a solution, described the situation as "unbelievable" and "a nightmare". Officially, the force adopted a different stance to police in other parts of the country.

The change affects people who have been arrested but not charged, and who have been released on bail while police investigate further. Often, officers are waiting for drugs, forensic evidence or DNA samples to be analysed before proceeding with a charge.

In more complicated cases, they may be waiting for CPS approval to charge them.

Suspects are released with conditions on their behaviour, such as barring them from contact with witnesses or victims, and a requirement to return on a given date.

Some suspects remained on bail for months, particularly in complicated investigations, including murder cases when bodies were missing, and the recent Hastings Pier arson inquiry.

The Association of Chief Police Officers was yesterday referring officers guidance, which said officers could not arrest people for breaking the terms of their bail.

Sussex Police said in a statement: "Our advice to officers is that bail is still valid along with bail conditions when they have been imposed.

"Defence solicitors have been advised to inform their clients they need to answer bail, and that they are liable to arrest for failing to comply with conditions."

One Sussex Police officer said: "I don't think there is a single person here who has got the same opinion as the next person."