The Leeds-based company, which owns the site, operates its print business on the neighbouring plot.

Staff at the company alerted police to a suspicious smell emanating from the premises, which turned out to be the product of 3,000 plants with a street value of £800,000.

Acting Inspector Sue Disley, of the West Outer Neighbourhood Policing Team, said the scale of the cannabis growing operation puts it among "the largest ever found in West Yorkshire and it represents a very significant seizure".

The growing operation was spread over two floors and had been sectioned off into separate rooms containing plants at different stages of the growing process.

The Wortley site has undergone a detailed forensic examination, the plants have been recovered for disposal and enquiries are ongoing to trace those behind the illegal operation.

She added: "Once again the vigilance of members of the public has played a vital role in stopping this drug reaching the streets where it can cause damage to individuals and our communities."