A council acted lawfully by not requiring planning permission for a barge housing asylum seekers because its powers do not extend to its location on the sea, the High Court has been told.

Carralyn Parkes, the mayor of Portland, is taking legal action against Dorset Council, claiming it was wrong to decide in July 2023 not to consider using its enforcement powers over the Bibby Stockholm ship.

Lawyers for Ms Parkes, who is bringing her case in a personal capacity, said she is “deeply concerned” about the 93-metre-long barge accommodating migrants in Portland Harbour and wants a judge to order the council to reconsider its position.

A hearing of her case beginning in London on Tuesday comes in the wake of Ms Parkes losing a bid to bring a High Court challenge against the Home Office over the lawfulness of ministers’ decision to house migrants on the barge.

In October, Mr Justice Holgate ruled she did not have an arguable case to bring against the Home Secretary.

Dorset Council is now defending against a fresh legal challenge, arguing its powers do not extend to the seabed above which the engine-less barge floats.

The Home Office and Department for Levelling Up, Housing and Communities, taking part in the hearing as interested parties, back the council’s position, arguing the case should be dismissed.

The Government has spent around £9.2 million on using the barge, with 315 people living there as of January 9 this year, Home Office lawyers told the court.

Penelope Nevill, representing Ms Parkes, said Dorset Council had reached an “erroneous” view that the “stationing and use of the Bibby Stockholm barge is outside the area within which it can exercise its planning powers”.

She added: “The entirety of Portland Harbour is within the county of Dorset and therefore within the council’s planning authority.”

In written arguments, Ms Parkes’s legal team said the Bibby Stockholm was “integrated into the local community, rather than being ‘out to sea’”, with the law allowing the council to take action when it is “in the public interest” and where a development could have a “substantial impact” locally.

They argued that her case had “wider significance” as to whether projects on dry land or inland waters would still be classed “developments” in enclosed bays and harbours.

The mayor’s lawyers said that the council’s position meant there was a gap in planning law that would allow more barges to be moored to piers and used as hotels, hostels, casinos and nightclubs.

Speaking outside court, Ms Parkes said she was convinced that if the council had consulted on planning permission for the barge it would have concluded that its location was unsuitable.

She said some people on the barge, including “torture victims”, should not be on board, describing it as “deplorable” and “confined” accommodation.

Richard Wald KC, representing the council, said in written arguments that Ms Parkes’s case was “absurd and unworkable”.

He wrote: “The council’s answer to this claim is straightforward: the ‘sea’, and therefore the seabed, cannot be ‘land’ for the purposes of the Town and Country Planning Act 1990.

“Planning law simply doesn’t extend below the mean low water mark, whether that be in a bay, harbour or anywhere else.”

He said “the seabed over which the Bibby Stockholm floats is not ‘land’”, adding that Ms Parkes’s lawyers had failed to show that Portland Harbour comes within the boundaries of Dorset.

The 222-room, three storied ship was towed into the harbour and moored to a “finger pier” in July last year, after the Government announced it would be used to house asylum seekers for at least 18 months.

The barge has since been hit by problems, delays and disputes, including the discovery of dangerous bacteria last summer that led to an evacuation, with it lying vacant for two months.

An inquest is also ongoing into the death of one asylum seeker thought to have taken his own life while living on board.

Last month, it was reported that the Home Office had shelved plans to procure more barges to hold asylum seekers amid struggles to find ports willing to take them.

The hearing before Mr Justice Holgate is due to conclude on Thursday, with a ruling expected at a later date.