PORT of Dover Police have been unable to legally carry out arrests since last November, the Express can reveal.
The force, which has some 60 officers and is managed by Dover Harbour Board, is under legislation which means its jurisdiction extends to the harbour, dock, pier and premises of Dover Harbour Board and within one mile.
But the axing of Dover Police custody suite last year has resulted in officers not being able to transport prisoners to the nearest suites at Canterbury, Folkestone and Margate because they fall outside the one-mile zone, rendering any arrest "unlawful".
The issue came to light after the port force sought legal advice in June and were informed that arrest and consequent transportation was illegal.
An inside source told the Express: "In November 2011 the Dover custody suite closed. The Port of Dover Police continued making arrests and transporting people to Folkestone, Margate or Canterbury but after legal advice in June they were told they were unable to make arrests or transport prisoners any more.
"Then Kent Police and port police made an agreement that Kent special branch officers will arrest prisoners and take them to the custody suites.
"It just seems a ludicrous situation that we have a police force that can't arrest anyone and Kent special branch, that is supposed to deal with terrorism and national security, is having to cover every day."
A change in the law is now being sought.
The Marine Navigation Bill, which seeks to extend powers of port police beyond the current one-mile radius, has been through a first reading in Parliament and is due a second on October 19.
The bill has been put forward by Tory MP Sheryll Murray and is being supported by members including Dover and Deal MP Charlie Elphicke.
Mr Elphicke said: "Yes, this is true.
"That is why we are trying to change the law. It's really important to extend the port police jurisdiction from one mile, so I have co-sponsored the Marine Navigation Bill, which is debated in October and will make this important change.
"The bill will make a big difference and solve this issue."
The bill, which will have a third reading before going to the House of Lords, is expected to be passed but not until the spring.
Plans are now being made by Kent Police Frontier Operations to provide cover in Dover in three phases from this month until next March.
In a message circulated to Frontier staff last week, ADCI Andy Somerville said a threefold hike in referrals from e-borders, which targets ferry manifests looking for suspects including those wanted by the county's forces for offences, was expected, necessitating steps to "bolster the Dover shifts with resources from around the Directorate".
The message also states: "This has been exacerbated by the fact that Port of Dover Police are currently unable to arrest suspects following legal advice from a QC, which in effect states that once beyond one mile from the port of Dover their officers no longer have the jurisdictional powers of a Police Constable, rendering any arrest unlawful at that point."
Kent Police said they will continue to help port officers.
Detective Chief Superintendent Chris Hogben, head of the Central Investigation department, said: "Kent Police have assisted their Port of Dover colleagues with a small number of arrests over recent months while the issue around their ability to exercise their powers beyond a mile from the port area is resolved.
"We have an excellent working relationship with the Port of Dover Police and while this is an example of officers assisting them, they continue to provide operational assistance to Kent Police on other issues.
"The fact that the Kent Police custody suites at Folkestone and Canterbury service the Dover area, including the port, has clearly brought the restriction on the use of the powers of the Port of Dover Police to the fore. We will continue to work with our partners to mitigate this issue until it is resolved.
"E-Borders related arrests are a matter for Kent Police and not the Port of Dover Police. Whilst historically the Port of Dover Police have assisted with such arrests, this remains a responsibility for Kent Police.
"The role of Special Branch and Frontier Operations Officers includes securing the border and protecting the people of Kent and the UK from criminals using the port, it is therefore right that they have involvement in arresting such people travelling through the port."
Dover Harbour Board maintained arrest powers are unaffected.