There are concerns that one of Britain's longest serving prisoners could soon be free after spending more than four decades behind bars.

Patrick Mackay, 67, has been dubbed ''Britain's Forgotten Serial Killer''. He killed a Catholic priest in the village of Shorne near Gravesend in the 1970s. In total, Mackay may have been responsible for as many as eleven deaths.

Mackay was put on trial at the age of 22 for the murders of Father Anthony Crean in Shorne and two elderly women in London. He was jailed in 1975 after being convicted of committing manslaughter on the grounds of diminished responsibility.

Now two men - the author of a new book about Mackay, and a former senior Kent policeman - both say that the Parole Board should think very carefully before Mackay is released.

In a statement the Parole Board confirmed that they are looking at the case.

"We can confirm the parole review of Patrick Mackay has been referred to the Parole Board and is following standard processes.

Parole Board statement

In his report Derek Johnson spoke to Ken Tappenden, a former Kent Police Commander who was involved in the original police investigation; and John Lucas, the author of 'Britain's Forgotten Serial Killer', which will be published by Pen & Sword Books in July.