Media playback is unsupported on your device Media caption John Cantlie's father, Paul, who has difficulty speaking, made his appeal from his hospital bed

The father of UK hostage John Cantlie has appealed for him to be released "to those he loves and who love him".

The journalist, who was kidnapped in Syria in 2012 and is being held by Islamic State (IS) militants, has so far appeared in three videos.

From hospital, Paul Cantlie said he felt "great relief" seeing his son for the first time in two years, but also experienced "despair and helplessness".

Meanwhile, IS has released a new video apparently showing a British jihadi.

I can think of no greater joy than seeing my dear son released and allowed to return home to us Paul Cantlie

The videos of Mr Cantlie, who is originally from Hampshire, have all followed the same format, with the journalist sitting at a desk against a black backdrop to address the camera.

In the most recent, released earlier this week, he delivered a scripted message mocking the US strategy of using air strikes combined with local ground forces.

At the end of the five-and-a-half minute film, he indicated there will be further messages.

There are no signs of violence in the videos but, in the first, Mr Cantlie made clear he was speaking as a prisoner whose life was in danger.

'Seeking true story'

His father said his family had been trying to deliver an "important message" to IS.

"For the first time in almost two years, we saw John when he made a televised broadcast during which he told viewers that he was still a prisoner of the Islamic State and that maybe he will live and maybe he will die," he said.

"As a family we experienced great relief seeing and hearing John and knowing that he is alive. This was followed by the feeling of despair and helplessness."

He said when his son was captured in northern Syria while working as a photojournalist, he was "seeking out the true story of the suffering of the Syrian people".

Image copyright John Cantlie Image caption John Cantlie was kidnapped in Syria in 2012

"John felt a strong need to help in the best way that he could," said his father. "As an impartial and respected journalist he knew that he could make a difference by acting as a platform for the world to listen to and take notice, using his journalistic skills for the good of the people, as a friend and as a civilian."

The Cantlie family is trying to communicate with IS "to deliver an important message regarding John" but has yet to receive a response, said his father.

In a direct message to the militants, he said: "To those holding John: please know that he is a good man, he sought only to help the Syrian people and I ask you from all that is sacred, to help us and allow him to return home safely to those he loves and who love him."

He said his family had received "many messages" of support.

"Speaking entirely for myself, this is not how I had imagined I would be passing my 81st year," he added.

"I want John to know how very proud I am of him. I can think of no greater joy than seeing my dear son released and allowed to return home to us."

Image copyright Other Image caption Mr Cantlie as he appears in the third video

BBC security correspondent Frank Gardner said to anybody with "an ounce of compassion", the video was "heartbreaking".

"This is a propaganda thing," our correspondent said of the IS videos featuring the captured journalist.

"This is about twisting the knife because they can't reply against the air strikes - they haven't got the ability to shoot down war planes."

The UK recently joined the US-led bombing campaign against IS after MPs voted overwhelmingly for British involvement in Iraq.

Hostages killed

John Cantlie - an experienced journalist and photographer - has twice been held captive in neighbouring Syria.

He was kidnapped in July 2012, and handcuffed and blindfolded for a week, but escaped with the help from the Free Syrian Army.

A second kidnap happened when he returned to Syria towards the end of 2012.

IS, also known as Isis or Isil, has taken control of large areas of Syria and Iraq and declared a caliphate.

Since August, the group has killed three Western hostages - US journalists James Foley and Steven Sotloff and British aid worker David Haines. They have also threatened to kill British hostage Alan Henning.

In the latest IS video, a man directly addresses Prime Minister David Cameron, saying: "If you were real men you will send all of your forces down on the ground - you will not bomb us from the skies... But you know that in the hearts of your men they're cowards."