The judge wrote to the then Home Secretary Michael Howard in 1995
Two convicted drug-smugglers facing 18-year jail terms gave false information to secure a significant cut in their sentences, a court has heard.
John Haase and his nephew Paul Bennett, provided "leads" about guns which had in fact been planted at their request, Southwark Crown Court was told.
The weapons were seized and the home secretary ordered the men's release a year after their conviction in 1995.
The men, of Merseyside, deny conspiracy to pervert the course of justice.
Mr Haase's wife Deborah, 37, of Teyham Avenue, Knowsley, Merseyside, and Sharon Knowles, 36, of Wadeson Road, Merseyside, deny the same charge.
Mrs Haase also denies the possession of firearms and ammunition without authority.
Gibson Grenfell QC, prosecuting, said that when the case went to court in August 1995 the men were sentenced to 18 years.
However, as a result of the information the men supplied about guns and ammunition, the trial judge wrote to the then Home Secretary, Michael Howard, suggesting an appropriate sentence would be five years.
The Royal Prerogative of Mercy was exercised and, as a result, both men were released in July 1996.
Mr Grenfell told the court that the men had arranged for the firearms and ammunition to be planted so they could then tell the authorities about them. One such haul was buried in a red squirrel reserve in Formby.
The men were arrested in July 1993 in Liverpool as part of an investigation into an international drug-trafficking operation.
Turkish crime syndicate
The court heard that Mr Haase, 59, currently of no fixed address, and Mr Bennett, 44, whose address is unknown, were both based in Merseyside, where they were the British end of a drugs-smuggling ring involving a Turkish crime syndicate.
"Following their arrest, it seems both men realised that the evidence against them was strong and that they would have to plead guilty," Mr Grenfell said.
"They decided to make an arrangement with HM Customs whereby they would provide information about the criminal activities of others."
The jury heard that Deborah Haase - who had yet to marry Mr Haase and was at the time Deborah Dillon - and Sharon Knowles were among the accomplices involved in planting the weapons.
Mrs Haase's fingerprints were found on black bin bags in a car in one of the seizures, which contained firearms, the jury heard.
Sharon Knowles was also linked to the seizures, the court was told.
The jury also heard that there was never any information or intelligence leading to the arrest of anyone connected with the caches of arms.
In addition, in some cases the cars where guns were found had been bought or stolen shortly before the male defendants divulged their information and that garages where guns were found had been rented by people who had given false details or were untraceable.
"These various features indicate that the series of seizures was a 'set-up'," Mr Grenfell said.
"In other words Haase and Bennett were not genuinely informing on real criminal activities, or telling the authorities about the guns in fact used by criminals, but, with their undoubted contacts and resources, setting up a scheme the purpose of which was to reduce their sentences."
The trial has been adjourned until Monday.