A missing aristocrat and her lover were last night finally found in after 54 days on the run but without their baby.
Fears for the infant were growing as police launched an urgent search operation after arresting aristocrat Constance Marten and Mark Gordon in a residential street following a tip-off from a member of the public at about 9.30pm on Monday.
Officers from Sussex Police attended the Stanmer Villas in Brighton and found the pair, who had been missing since January 5. They remained in custody early this morning.
The Metropolitan Police said they were worried about the couple's baby, who is not thought to have had any medical attention since being born in early January.
Fears for the infant were growing as police launched an urgent search operation after arresting aristocrat Constance Marten and Mark Gordon in a residential street following a tip-off from a member of the public at about 9.30pm on Monday
Constance Marten and Mark Gordon on Avis Road, Newhaven
A member of the public reported a sighting in Stanmer Villas, Brighton
Marten, 35, and Gordon, 48, have thought to have been travelling around the UK by taxi since their car was found burning on the M61 in Bolton, Greater Manchester, on January 5.
Authorities previously believed the couple had been sleeping rough in a blue tent, and had avoided being traced by the police by moving around frequently and keeping their faces covered in CCTV images.
The couple travelled from Bolton to Liverpool, then to Harwich in Essex, then to east London and then to Newhaven in Sussex, where they were seen near the ferry port on January 8.
Miss Marten, who is from a wealthy aristocratic family, was a promising drama student when she first met Mr Gordon in 2016.
Since then the couple have led an isolated life, and in September, when Miss Marten was well into her pregnancy, began moving around rental flats.
It is unknown if their baby was full-term or has any health issues.
The mother of the missing aristocrat previously issued an emotional open letter to her daughter.
Virginie de Selliers pledged to stand by Marten, 35, and her grandchild, telling her in an emotional open letter: 'You are not alone in this situation. We will support you in whatever way we can.'
She added: 'I know you well enough; you are focused, intelligent, passionate and complex with so much to offer the world. So many of your friends have come forward to say such positive things about you, assuring us of their warmest love and support for you and your family.
The Met Police said officers were searching urgently for the couple's baby in Brighton after the pair were found following a sighting reported by a member of the public
Numerous police appeals for the couple to come forward had been made before last night's discovery
Police searching for the aristocrat missing with her boyfriend and their newborn were offering a £10,000 reward to find them.
'You have made choices in your personal adult life which have proven to be challenging, however I respect them, I know that you want to keep your precious new-born child at all costs.
'With all that you have gone through this baby cannot be removed from you but instead needs looking after in a kind and warm environment.
'I want to help you and my grandchild. You deserve the opportunity to build a new life, establish a stable family and enjoy the same freedoms that most of us have.
'Constance, I will do what I can to stand alongside you and my grandchild. You are not alone in this situation. We will support you in whatever way we can.
'I am ready to do what it takes for you to recover from this awful experience so you can thrive and enjoy motherhood.
'I love you and miss you, Mum xx.'
The investigation to find the couple started when officers were called to a car on fire on the hard-shoulder of the M61, near junction four (Farnworth, Bolton) at 18:33hrs on Thursday, 5 January. However, the occupants were not at the scene.
Enquiries revealed that Constance and Mark were the occupants of the car and that Constance had very recently given birth, possibly one or two days before, and had not been assessed by medical professionals.
Metropolitan Police said an urgent search operation is underway to find their baby, who has not had any medical attention since birth in early January
January 7: CCTV footage shows Marten and Gordon on Whitechapel Road in London
January 7: Marten was spotted outside Harwich Port at 9am and later Colchester
January 7: Constance Marten and Mark Gordon outside East Ham station at around 11.45am
Last sighting: Marten and Gordon were last spotted on Avis Road, Newhaven
A missing persons investigation was launched by Greater Manchester Police, who established that the family left the vehicle and the motorway safely – walking to the Anchor Lane bridge which links the Highfield and Little Hulton areas.
Officers had said they believe they then travelled to Liverpool and then onwards to Harwich via a taxi at about 03:30hrs on Friday, 6 January.
Mark, Constance and a baby were seen by a member of the public in Harwich at about 09:00hrs on Saturday, 7 January. Officers also received a number of confirmed sightings of the family in Colchester on Friday, 6 January and Saturday, 7 January.
Subsequently, the investigation was handed over to Essex Police on Monday, 9 January.
Essex Police carried out a number of enquiries and reviewed hours of CCTV and were able to place the couple near East Ham Station between 10:30hrs and 12:30hrs on Saturday, 7 January.
As this was the last confirmed sighting of the family at the time, the investigation was handed over to the Metropolitan Police Service on Thursday, 12 January.
Detectives then established that they took a taxi from East Ham, being dropped off in Whitechapel Road at 6.14pm on Saturday, 7 January.
The couple are seen leaving the taxi with an orange carrier bag and a pram. They both have their heads and faces covered and Mark is wearing white plastic bags on his shoes, which he removes a short time later.
At 18:19hrs Mark went into Argos on Whitechapel Road, E1, and bought two big bags full of items, paying in cash, including a blue two-man tent, two sleeping bags and two pillows – which sparked fears they have been camping, including at times when the temperature plummeted to sub-zero.
They spent the next few hours walking along the Whitechapel Road area, where they tried to flag down three taxis but were refused. They then walked to the Brick Lane area.
At about 11.46pm on Saturday, January 7, they then went to Flower and Dean Walk near Brick Lane where they dumped a number of items, including the pushchair. They then got a taxi to Haringey.
At 1:24am on Sunday, January 8, they then got in another taxi in Allison Road, Haringey, and travelled to Newhaven, where they were dropped off just outside the port at 4:56am.
Anyone who may be able to assist in the search for the couple's baby is urged to contact 999.
A Met Police spokesperson told MailOnline: 'There's a huge search operation going on at the moment. There are no further details.'