Iranian state TV has seized on comments made by Boris Johnson on a detained British-Iranian mother as an unintended "confession of her real plot".

A news bulletin aired on Iranian television on Wednesday night on a segment called “Confession”, the host referred to the Foreign Secretary's comments as evidence that Nazanin Zaghari-Ratcliffe was conducting illegal affairs in Iran.

Mrs Zaghari-Ratcliffe, who was in Iran with her two-year-old daughter at the time of her arrest last April, has always stated she was in Iran on holiday visiting family.

“Mr Johnson’s inadvertent confession meant that [she] was teaching some Iranian journalists – it was a gaffe that can not be covered up. The sole sentence uttered from the mouth of the UK foreign secretary put the efforts of the British media [propaganda] in vain," the segment on Channel 2 claimed.