CNN has apologised after a technical glitch led to the station using a photograph of Vladimir Putin to illustrate a story about Jihadi John's true identity.

The mistake came as Max Foster, CNN London correspondent, discussed the fate of hostages held by the ISIS and the possibility that Jihadi John, identified this week as Mohammed Emwazi, would ever face justice.

Half of the split screen switched from the chilling picture of the masked terrorist wielding a knife to an image of the Russian president before it was quickly removed.

A spokesman for CNN told the Tass news agency: "Due to a failure of a video server during today's breaking news broadcast, a photo of Vladimir Putin, prepared for our next report, was accidentally shown.

"We apologise for that mistake."