Officers discovered the set up in a factory unit off Premier Street at around 7.30pm on Thursday, October 8.
They uncovered the drugs den with more 1,000 plants while carrying out enquiries into a robbery in Premier Street.
A man in his 50s was assaulted as his car and cash were taken during the robbery, although the Bentley has since been recovered.
WMP is keen to hear from anyone with information about the robbery and the cannabis factory.
Investigations are ongoing. Contact the police via Live Chat, or by calling 101, and quote 20BW/244909G/20.
