Lindsay Foreman and her husband Craig Foreman were detained during a round-the-world motorbike trip at the start of 2025.

The couple were sentenced in February to 10 years in prison on espionage charges that they deny.

"It is now emerging that their appeal against a ten-year espionage conviction has failed," their son, Joe Bennett, said in a statement.

He said the couple were "not permitted to attend their own appeal hearing" and were asked to sign documents in Farsi, but had so far refused as they did not understand them.

The case has "now passed to the Supreme Court", Bennett said, "but we don't understand the process, the timeline, or what, if anything, will be submitted in their name".

The couple are no longer being represented by their court-appointed lawyer, he said.

The couple's family have urged the British government to do more to help the couple.

Bennett said he met on Monday with British Foreign Office officials, who were "very kind. But kind is not the same as doing something to enable their release".

A Foreign Office spokesman said: "We are disappointed by the appeal decision and will continue working to ensure that Craig and Lindsay are returned safely to the UK."

The spokesman added the couple's continued incarceration was "unjustified and appalling".

Both have launched hunger strikes, with Craig now on his 25th day and Lindsay on her 16th day, according to their family.

The family has said it fears they could be killed in the war in Iran as there have been explosions near the Tehran prison where they are held.

The couple travelled to Iran after ignoring warnings from friends, family and the UK foreign ministry, which advises against all travel to Iran.

They are just the latest of numerous Westerners held by Iran since the 1979 Islamic revolution, with Tehran accused of so-called "hostage diplomacy" to extract concessions from its foes in Europe and from the United States.