Portsmouth City Council has served an encampment of around 20 vehicles with an eviction notice yesterday after they arrived in a field by Marina Keep on Monday evening.
And according to the city's community safety lead, police are investigating the breaking of a reinforced gate that allowed access to the site.
A spokeswoman for Portsmouth City Council said: ‘Our community wardens (yesterday) served section 77 notices on the unauthorised encampment at Port Solent.
‘We will continue to work closely with the police on this matter.’
Councillor Lee Hunt, the council’s cabinet member for community safety, said: ‘We will treat all unauthorised encampments the same way, it doesn't matter if it's travellers, a chapter of Hells Angels or the Women's Institute.
‘We would go through the same process as it's public property and they should not be there.
‘I have seen the pictures where someone has cut through the reinforced gates at Port Solent and that is a crime. I believe the police are making enquiries into it.
‘We put the new gate in last year after someone cut through padlocks and this time we put in a reinforced gate with a metal hood over the top at great expense to the public purse. Someone must have taken a disc cutter to it to cut through.
‘I hope whoever did it is caught and charged by the police.
‘We have to protect our open spaces for the residents.’
As reported, clear-up costs and repairs to the barriers in the same field last year cost the taxpayer around £13,000.
It comes as an unauthorised encampment recently left the field behind Clarence Pier in Southsea, having been served an eviction notice.
The council spokeswoman said: ‘The unauthorised encampment at Pembroke Gardens left the site and city on Tuesday evening following the service of an eviction notice by the community warden team.’
Last week council workers were seen distributing large rocks around the border of part of Southsea Common, by Southsea Terrace, to deter people driving vehicles on to the grass.