According to the Iranian judiciary's spokesperson Asghar Jahangir, the couple, who were arrested in the province of Kerman in January, have collaborated with "secret institutions linked to the intelligence services of hostile and Western countries".
The couple are said to have traveled around the world on motorcycles when they were arrested in Iran. According to British media, they entered the country from Armenia at the end of December with plans to then head to Pakistan.
The British government advises against all travel to Iran.
The British Foreign Office says in a statement on Tuesday that "we are deeply concerned about reports that two British citizens have been accused of espionage in Iran" and that they will continue to take up the matter "directly with the Iranian authorities".
