A man was arrested after police raided on a cannabis factory in a residential street.
Officers were called out to a home in Montgomerie Road, Southsea, amid reports of suspicious activity at about 5.45pm on Wednesday.
But when they arrived they discovered the front door to the terraced property was open and went inside to investigate.
Once inside they found the first floor had been transformed into a cannabis factory.
High powered artificial lighting equipment used to grow the drug was also discovered.
Moments later a 42-year-old man arrived at the house and was arrested on suspicion of cultivating cannabis and possession of the class B drug.
He was also quizzed on suspicion of using electricity without authority.
The suspect was later released on police bail until February 24 pending further enquiries.
Yesterday police officers worked to remove the class B drugs and paraphernalia used to cultivate it from the property.
It is not yet known exactly how much cannabis was seized.
However The News understands it was a sophisticated operation and the number of plants seized could run into hundreds.
One local resident, who does not want to be named for fear of repercussions, said: 'I can't believe it.
'We had no idea there was a cannabis factory down the road.
'You hear about this sort of thing happening all the time but you don't expect it where you live.
'It doesn't bear thinking about.'
A Hampshire Constabulary spokesman said: 'Police would like to hear from anyone, particularly neighbours, who saw anything suspicious around the address on Montgomerie Road.'
The find comes less than two months after police uncovered another cannabis factory at a home in Fareham.
Officers made the discovery after being called to a burglary in Shearwater Avenue shortly after midnight on November 5.
Anyone with information is asked to contact PC Steve Galmoye-Webster from the Targeted Patrol Team at Southsea police station on 101 or Crimestoppers on 0800 555111.