Q&A: Who is Constance Marten and why are UK police so concerned for her baby's welfare?

Handout file photo issued by the Metropolitan Police of a CCTV image dated January 7 of Mark Gordon and Constance Marten on Whitechapel Road in London.

Police in the UK are continuing to search for a missing baby after two people were arrested on Tuesday on suspicion of gross negligence-manslaughter.

Constance Marten and her partner Mark Gordon, who had been reported missing in January, were taken into custody after a member of the public spotted them.

It had been 54 days since the pair were last seen.

Ms Marten was a promising drama student when she first met Mr Gordon.

Since then, the couple have lived an 'off-grid' life, and in September, when Miss Marten was well into her pregnancy, began moving around rental flats and Airbnbs

Here, we answer some key questions about the case.

Who is Constance Marten?

Constance is the granddaughter of Mary Anna Marten — who was a playmate of Princess Margaret, the sister of Queen Elizabeth II.

Mary Anna Marten was the goddaughter of Queen Elizabeth's mother.

Constance had grown up on the 5,000 acre Crichel House estate in Dorset, England, before attending a drama school — however, a falling out with a tutor led to her leaving in 2016.

Her father, Napier Martin, was a page to Queen Elizabeth II.

Who is Mark Gordon?

Mark Gordon is Constance's partner.

He was jailed in the late 1980s for 20 years for rape and battery after an attack on a woman when he was aged 14 in Florida.

He was deported to the UK in 2010 and is believed to have met Ms Marten in 2016.

When did Constance Marten go missing?

An abandoned car was found in Bolton on January 5 but the pair were spotted by police in Essex just after midnight the following morning.

Officers have since established the couple took a taxi from East Ham rail station while Gordon was spotted leaving an Argos after purchasing a tent on January 12.

Later that evening, they were last seen walking along Cantercrow Hill into the fields beyond on January 12.

Where were the couple found?

The duo were found by officers from Sussex Police in Brighton on February 27, along with their newborn baby, after a member of the public reported seeing them shortly before 9.30pm.

However, their baby was not with them at the time.

Detective Superintendent Lewis Basford of the Metropolitan Police has suggested the couple may have offered their “cash reserves” to someone in exchange for them protecting their baby.

“We hold hope the baby is safe and we agree that the risk is extremely high,” he told reporters.

Why have Constance Marten and Mark Gordon been arrested?

The couple were initially arrested on suspicion of child neglect but on Tuesday evening (February 28) were rearrested on suspicion of gross negligence manslaughter.