A 36-year-old man has been warned by a judge to expect an immediate prison sentence. His young female co-defendant is to have a trial over issue to determine the extent of her knowledge of what was going on at the 500-plant farm.

Preston Crown Court was told the true age of the female defendant, Lan Phan, was not known, but following an assessment a judge at an earlier hearing ruled she was 'at least 17'.

The woman, together with Lap Tran, 36, pleaded guilty to conspiracy to produce cannabis at their address on Acregate Lane, Ribbleton, between September and October last year.

They admitted 'conspiring together with others unknown' to produce the Class C drug.

Their not guilty pleas to extracting electricity for the same month were accepted by the prosecution.

Prosecutor Paul Brookwell told the court: "Police found a sophisticated system. Both defendants were effectively farmers."

Others must have been involved in the conspiracy, he added.

Andrew Alty, defending Tran, told Judge Phillip Sycamore: "He accepts that once he was there he knew what was going on and he assisted for a month."

Richard Hunt, defending Phan, said: "The matters which the court would have to decide on about her involvement would probably not affect the fact that she would eventually be deported."

Judge Sycamore said the trial into the issue of her true involvement in the conspiracy would take place next month.

Both defendants will return to Preston Crown Court for sentence on April 3.

Each was remanded in custody.