Police are continuing their investigations into a large cannabis factory discovered on farmland in the Fens last week.

Officers found more than 1,000 cannabis plants being grown under a sophisticated set-up with lights and ventilation installed in a self-contained unit within a barn last Thursday evening.

It is understood no one was on the premises when officers arrived but police believe somebody had been in the barn, in Terrington St Clement, earlier in the day.

Forensic examinations have now finished and police officers have cleared the site, just off Station Road and close to the busy A17, of all the plants. It is believed the cannabis plants have a combined street value of �100,000.

A Norfolk Police spokesman today confirmed no arrests have been made and that investigations are continuing.

Speaking to the media last Friday, Det Sgt Warren Witt said: 'It's a big haul and it is up there with some of the biggest ones we have come across – it is certainly one of the biggest in West Norfolk.'

He later added: 'There are 12 individual chambers in here with plants all at different stages of growth. There is no indication at the moment how long they have been here for.'

People working nearby the barn have previously spoken of their shock at the cannabis factory discovery. They also revealed how they had noticed increase activity at the site over the last couple of months.

Anyone with information is asked to call Norfolk police on 101.