The father of captured British journalist John Cantlie has urged Islamic State militants to return his son to safety.

"My family and I are trying to communicate with the Islamic State to deliver an important message regarding John, and can only hope that it has been received as we have had no response," Paul Cantlie said in a recorded statement.

"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 those who love him," he added.

He said the family had experienced "great relief" from seeing videos of John that were released by the militant group - the first time the family had seen him since his capture in 2012.

However, he said that feeling was followed by "despair and helplessness".

Here is the transcript of his message in full:

My name is Paul Cantlie. My son John Henry Cantlie has been held as a prisoner by the Islamic State since 2012. Paul Cantlie

Full transcript of John Cantlie's first IS video