CHILLING new footage has shown Constance Marten and her rapist partner dumping their newborn baby's pram.
Cops are offering a £10,000 reward in the search for missing aristocrat Constance and her former convict partner Mark Gordon.
The pair were last seen with their baby, in Newhaven, East Sussex on January 9, police added.
The family have been missing since their car broke down and burst into flames on the M61 on January 5.
Shortly before going missing, Constance, 35, gave birth to Gordon's child "with no medical attention".
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They are believed to have been sleeping rough after being spotted buying camping equipment from an East London Argos on January 7.
The same day, they were seen on grainy CCTV dumping the baby's pram in the port town at 11.46pm.
The Metropolitan Police confirmed that they were last seen in Sussex on July 9 but are believed to still be in the country.
Detective Superintendent Lewis Basford, who is leading the investigation into their disappearance, said: "We continue to be extremely concerned about the health and wellbeing of the newborn baby, which has had no medical care and has been on the move, and possibly exposed to sub-zero temperatures, for almost a month now.
"We're also concerned for the welfare of Constance and Mark because our enquiries suggest that they were constantly moving and awake for at least a few days - which must be especially draining on someone who had recently given birth with no medical attention.
"Finding the baby is our top priority and we are now offering a £10,000 reward to anyone who provides information which leads to them being found."
DS Basford added: "We have no evidence to suggest that they boarded a ferry in Newhaven, and we still strongly believe that they remain here in the UK – although they could be anywhere.
"Our enquiries also establish that the baby was alive and with them when they got the taxi to Newhaven.
"We know they were still in possession of camping equipment on January 8 and so I'd encourage people to remain vigilant and keep a look out for a blue tent.
"Please keep your eyes peeled, especially while you are out and about in waste ground or beauty spots, or while you're walking the dog, and report any information to us."
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It comes after an old pal revealed that Constance "could have gone very far" as an actress before she became estranged from her aristocratic family.
In fact, Constance was deemed an 'It girl' when she appeared on upmarket mag Tatler's babe of the month page while she was a student in 2008.
The daughter of Napier Martin, a former page to the Queen, and granddaughter of Mary Anna Marten, whose godmother was the Queen Mother, Constance comes from a family of wealthy landowners.
It is believed that she paid for her time at drama school via a multi-million pound trust fund stored at C. Hoare & Co, the UK's oldest private bank.
However, she has reportedly led an isolated life since moving in with Gordon in 2016.
The 48-year-old is a convicted sex offender who served 20 years in a US prison for rape and battery.
He was convicted for attacking a woman in Florida when he was just 14.
His victim recently revealed that he held her captive and threatened to kill her children if she screamed during the horrific attack.
