McCann family spokesman Clarence Mitchell said: “The investigators are pleased to hear that Mr Hewlett has agreed to speak to them.

“An interview with him will be arranged and will take place in due course.

“We will not be going into public detail about where or when that interview will take place. Mr Hewlett has again denied any involvement in Madeleine’s abduction, and if it helps to eliminate him from the private investigation then he has done the right thing by indicating that he will speak to the investigators currently helping Liverpool-born Kate and Gerry McCann.”

British-born Hewlett, a former soldier who previously lived in Blackpool and Telford, is reportedly being treated for throat cancer in Aachen.

He was jailed several times in the UK for sexually assaulting young girls, including an attack in 1978 where he put a gun to his victim’s back.

He was also questioned over the 1975 murder of 11-year-old Lesley Molseed. Another man was eventually convicted of the crime in 2007.

West Yorkshire Police has confirmed its officers want to speak to Hewlett in connection with an indecent assault in 1975.

Madeleine was nearly four when she went missing from Praia da Luz while her parents dined with friends nearby.

Despite a massive police investigation and huge publicity worldwide, she has not been found.

Hewlett protested his innocence and insisted he was prepared to meet the McCanns’ investigators.

He told reporters outside the hospital in Aachen: “I have nothing to hide. I am willing to talk with them.”