The father of a missing aristocrat last seen in London with her newborn baby and partner has urged her to contact police.

Napier Marten, reportedly a former page to the late Queen, said he and his family are “deeply concerned” for the welfare of Constance Marten and her baby.

Constance comes from a wealthy aristocratic family, while her partner Mark Gordon is a sex offender who served 20 years in a US jail for rape and battery.

READ MORERenewed appeal to find missing family last sighted in London

His conviction relates to a Florida attack on a woman in her early 20s when he was 14.

The couple have been missing for almost two weeks and police said they have a substantial amount of cash, allowing them to live off-grid.

They were last spotted at East Ham Station on January 7.

The couple are understood to have lived an isolated life since meeting in 2016, with then-drama student Ms Marten cutting off ties with family and friends.

In an audio appeal, made through The Independent, Napier said while he remains estranged from his “darling” daughter, his family is willing to “do whatever is necessary for your safe return to us”.

Newham Recorder: CCTV footage captures Constance MartenCCTV footage captures Constance Marten (Image: Met Police)

In his appeal, Napier said: “Darling Constance, even though we remain estranged at the moment, I stand by, as I have always done and as the family has always done, to do whatever is necessary for your safe return to us.

“I beseech you to find a way to turn yourself and your wee one in to the police as soon as possible so you and he or she can be protected.

“We are deeply concerned for your and your baby’s welfare."

READ MOREMissing couple and newborn baby sighted in east London

Constance grew up in Crichel House, a Dorset estate, as part of an eminent family with links to the royals.

The Sunday Times said her grandmother was a playmate of Princess Margaret, while her father was a page to the Queen, who died last year.

Last September, Constance and Mark began moving around the country, renting AirBnBs for brief periods.

On January 5, they were on the M61 when their car broke down and caught fire near junction four at Farnworth, Bolton.

Newham Recorder: Constance Marten and Mark Gordon's car caught fire almost two weeks agoConstance Marten and Mark Gordon's car caught fire almost two weeks ago (Image: Met Police)

The couple then walked to Anchor Lane Bridge, where they got a taxi to Liverpool before getting another to Harwich, Essex.

They were seen around Colchester on January 6 and when they took another taxi to East Ham Station on January 7.

Investigators say the couple appear to know how to evade authorities – making the search for them harder.

Police believe they could be anywhere in the UK and are appealing to the public to come forward with any information that may help find them.

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

Anyone who has information on the family’s whereabouts is asked to call the incident room on 020 7175 0785.

Information can also be reported anonymously to the independent charity Crimestoppers on 0800 555 111.

Reporting by PA.