Im Peng Chen (51), a mother of three, had initially denied cultivating 613 cannabis plants which were found by police during an anti-drugs operation at a house in Templeard in the Culmore area of the city last January. But she was re-arraigned yesterday and admitted the offence before Judge Desmond Marrinan.

The court was told that Chen was "a cannabis gardener" and that the value of the drugs found in the house was £306,000. Almost £750,000 of cannabis plants were found in three other houses searched during the same police operation.

A prosecution barrister told the court that Chen had travelled to Northern Ireland on a Taiwanese passport which subsequently had expired. Initally she worked in restaurants before "she was approached by individuals and was paid only for her lodgings to become a gardener for the cannabis".

A defence barrister said Chen had been taken advantage of and added that she had not seen her children who were still in China for four years. During her eleven months in custody for the cannabis offence , her father had died.

Jailing Chen for eighteen months, Judge Marrinan said he accepted that she was a victim in a vulnerable situation who had been abused by others.

"I see her very much as a victim rather than as a serious player in this operation", he said.

A police officer told the court that , in 2008 alone, ten large cannabis factories had been found by the police in Derry and L i mavady.