GARDAÍ have reduced their estimated value for ecstasy tablets, sparking fears of a series of legal challenges by individuals caught in possession of drugs.

Gardaí had been operating on the basis of a €10-per-tablet estimated value for ecstasy until earlier this year.

However, they recently conducted a review of all street drug prices and now appear to have decided that ecstasy is worth just half that.

During a recent seizure of the pill in Dublin, gardaí quoted a 1,000-tablet haul as having a "street value in the region of €5,000". The revaluation is sure to lead to legal challenges by those facing lengthy sentences for possession of large quantities of ecstasy.

All offenders caught with more than €12,500 worth of drugs face a mandatory jail sentence of 10 years.

The new valuation means that some individuals already charged with drug offences will be faced with prison terms based on higher values.

Last year, it emerged that gardaí had revalued cannabis, but this time the price rose from a low of €2 per gram to a high of €12 per gram.

The change led to a possible legal loophole, which was taken advantage of by a 25-year-old Englishman who was found not guilty of drug charges.

His legal team successfully argued that the original valuation by gardaí of cannabis worth €45,925 was too high, based on a per-gram value of €9 quoted by gardaí during the case. His lawyers argued that a valuation of €2 per gram – or €10,205 in total – was fairer based on a garda circular from 2004.

The man had already pleaded guilty to the charge of un­lawful possession of drugs but was found not guilty of a more serious charge, for which he would have faced the mandatory 10-year sentence.

Some gardaí are echoing calls by lawyers that drug cases should be tried on the basis of quantity of drugs rather than artificial street values.