Islamist terrorists have beheaded the Canadian hostage John Ridsdel, 68.

Justine Trudeau, prime minister of Canada, condemned the killing as an act of "cold-blooded murder".

Ridsdel, a former mining executive, was seized with three others from a popular holiday resort in the Philippines.

The Abu Sayyaf group kidnapped Ridsdel, along with fellow Canadian Robert Hall, Hall's Philippine girlfriend Maritest Flor and a Norwegian, Kjartan Sekkingstad, in September last year.

The Islamists then released a video last November demanding a £55 million ransom for all four.

Ridsdel's severed head was found on Jolo, a remote island, soon after the ransom deadline expired yesterday.

Trudeau said it was a "heinous act".

He said: "Canada condemns without reservation the brutality of the hostage-takers, and this unnecessary death. This was an act of cold-blooded murder and responsibility rests squarely with the terrorist group who took him hostage."

Bob Rae, a friend of Ridsdel, told CBC News: "It's hard, it's just very hard. I've been involved behind the scenes for the last six months trying to find a solution and it's been very painful."

Abu Sayyaf is a small ultra-extremist separatist group from the southern Philippines, and gets some funding from Al Qaeda.

The Philippines are mainly Catholic.

The group was responsible for a 2004 ferry bombing in Manila Bay which killed 100 people.