A British couple detained in Iran for seven months on espionage charges have been moved to separate prisons in and near Tehran, heightening fears for their welfare, their son told AFP on Monday.

Lindsay and Craig Foreman, both 52 and who previously split their time between southeast England and Spain, were seized in Kerman, in central Iran, in early January while on a round-the-world motorbike trip.

Their family has known little about their whereabouts since then, but say they learned Sunday via the UK Foreign Office that Lindsay has been transferred to Qarchak women's prison near the capital.

It has a dubious reputation, with human rights groups repeatedly criticising dire conditions reported there.

"It's one of the worst prisons in the world," Lindsay's son Joe Bennett said in an interview Monday near his home in Folkestone, southeast England.

Meanwhile, his stepdad Craig has been moved to Tehran's infamous central prison, also known as Fashafouyeh, which is about 30 kilometres (18 miles) south of the capital and has similar notoriety.

Bennett, who has yet to talk to his parents since they were detained........

© Al Monitor