Constance Marten and Mark Gordon were last seen at East Ham Station (Picture: PA/Met Police)

A man who has gone missing with an aristocrat and their newborn baby is a sex offender who spent 24 years in a US jail, it has emerged.

British citizen Mark Gordon, 48, was deported after serving his sentence for raping and beating a woman in her 20s in Florida when he was 14.

He and Constance Marten, 35, have been ‘off grid’ with their child since their car broke down and caught fire on the M61 in Bolton on January 5.

She has access to a multi-million pound trust fund and police say they appear to have lots of cash on them, allowing them to avoid making digital payments that could be tracked.

Ms Marten grew up on her family’s Crichel House estate in Dorset, which was put on the market for £100million in 2010 before its sale to a US buyer.

Her grandmother was a playmate of Princess Margaret, while her father Napier Marten was a page to Queen Elizabeth, The Sunday Times reported.

Gordon served 24 years in the US for rape (Picture: Greater Manchester Police/PA)

Marten and her baby have not had medical attention since she gave birth (Picture: Greater Manchester Police/PA)

But the couple are understood to have lived an isolated life since they met in 2016, with then-drama student Ms Marten cutting off ties with family and friends. Police are worried for the newborn and say neither Ms Marten nor the baby have received medical attention since the birth.

After their car caught fire, the couple got a taxi to Liverpool before getting another to Harwich, Essex.

They were spotted in Colchester on January 6 and 7 before taking a cab to East Ham station in east London, where they were last seen.

Marten and Gordon outside East Ham Station at around 11.45am on January 7 (Picture: Met Police)

Some 200 police are helping with the search but they say the couple appear to know how to evade authorities, such as by hiding their faces on CCTV and keeping their baby covered up.

Investigators said it is unusual for hotels to accept cash payments and appealed to staff at places where the couple may stay to come forward.

Det Supt Lewis Basford said: ‘There is nothing to suggest that any of them have come to any sort of intentional harm – we just need to ensure they are OK, especially the baby, and do not require any medical assistance.’

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The couple have evaded being tracked down by using cash, police said.