The Court of Appeal gives its ruling today in a case involving people who claim they were tricked into forming relationships with undercover police officers.
The group are challenging aspects of decisions taken by Mr Justice Tugendhat at London's High Court in January.
He said it would not be an abuse of process at this stage to pursue the cases brought under common law by 10 women and one man, who want compensation for emotional trauma allegedly caused by officers infiltrating environmental activist groups.
But he said that claims brought under the Human Rights Act against the Metropolitan Police and South Wales Police should be determined by the Investigatory Powers Tribunal (IPT), which holds a number of hearings in private and has no obligation to take oral evidence.
He also stayed the High Court proceedings pending the determination of proceedings at the IPT, saying it was temporary and should not be long if the IPT claims were pursued expeditiously.
The women say they had a sexual relationship with a man who was later discovered to be a covert human intelligence source (CHIS), while the male claimant alleges a non-sexual relationship.
The police had argued that the IPT, which was formed in 2000, was the appropriate forum for all the claims as Parliament intended such cases to be decided by a specialist tribunal with a specially tailored procedure.
Some of the claimants say they had relationships with Mark Kennedy, the undercover police officer who spent seven years spying on environmental activists posing as Mark ''Flash'' Stone.