The head of global ports operator DP World has left the company after mounting pressure over his links to convicted sex offender Jeffrey Epstein.

Sultan Ahmed bin Sulayem's exit as chairman and chief executive comes after newly released files showed that the Emirati mogul appears to have exchanged hundreds of emails with Epstein over a decade.

Being mentioned in the files does not indicate any wrongdoing, and the BBC has approached Sulayem for comment.

DP World announced his resignation, "effective immediately", on Friday, naming Essa Kazim as chairman and Yuvraj Narayan as chief executive. A photograph of Sulayem appeared to have been removed from its website.

DP World, the Dubai-owned logistics giant that operates port terminals across six continents and plays a significant role in global trade infrastructure, has come under increasing pressure in recent days from the businesses it works with.

Earlier this week, the UK development finance agency and Canada's second largest pension fund La Caisse said they were suspending new investment into the firm.

And the Prince of Wales' Earthshot project, which received funding from DP World, was reported to the UK Charity Commission after Sulayem appeared in the files.

The documents reveal what appears to have been a close and wide-ranging relationship between one of the Gulf's most influential business figures and Epstein.

They indicate Epstein introduced Sulayem to various international figures from politics and business by email, and that Sulayem gave the Prince of Wales a tour of DP World's London Gateway port in 2016.

Sulayem was also accused by two US lawmakers, Ro Khanna and Thomas Massie, of being one of "six powerful men" who were associated with the disgraced financier.

The congressmen, who co-sponsored the law that compelled the justice department to release the Epstein files last year, say they were improperly redacted.

Among the redactions flagged by Massie on 9 February was a document appearing to show an email from Epstein in 2009 referring to a "torture video". The recipient replied that they would be travelling between China and the US. The context is not known.

US officials disclosed that Sulayem was the recipient behind that email from Epstein.

'Trusted friends'

According to a BBC News Arabic analysis of the documents, the emails appear to indicate Sulayem appears to have been in contact with Epstein as far back as 2007.

The trail of emails suggest the two developed a close friendship, regularly sending each other their travel plans, business ideas and contacts as well as news articles and crude jokes.

Epstein described Sulayem as "one of his most trusted friends" in an email from June 2013.

The men discussed business ideas worldwide, including Dubai, launching an "Islamic" digital currency.

Meanwhile, in several emails over the years, it would appear Sulayem sought Epstein's advice on health matters concerning himself, his daughter and his wider family and friends.

They apparently stayed in touch until at least 2017, two years before Epstein's death and despite Epstein's first criminal conviction in 2008 for soliciting and procuring a person under the age of 18 for prostitution.

Emails about women

The emails appear to indicate that Sulayem and Epstein exchanged many messages discussing girls and women around them.

The context of those emails is not always clear.

An email apparently sent from Sulayem to Epstein in 2013 regarding the arrival of two women disparaged the "Moldavian" as less attractive than her photo while praising the "Ukrainian".

Four years later, emails appear to indicate Sulayem arranged for Epstein's "private masseuse" to be trained on "all the treatments" at a Turkish hotel. A contact at the hotel confirms that she will receive an "an extensive training programme".

The email trail shows that the woman confirms she holds a Russian passport.

In an unrelated email in 2015, Sulayem told Epstein that he thinks "Russia is the source of all beautiful women".

Two separate emails, which appear to be from Sulayem, revealed he had an Irish and Uzbek girlfriend. In 2017, he boasted, "This is my new 22-year-old Uzbek" to Epstein. Epstein corrects him and appears to make a comment about her age: "According to her passport, she is now 23, old".

His correspondence with Epstein over the years suggests he was married and had two wives at one point.

On at least one occasion, Sulayem also appears to have forwarded his friend sexist and racist jokes.

Mandelson told 'Be nice to Sultan'

Lord Mandelson appears to have been lobbied by Epstein on behalf of Sulayem, who was trying to push through a deal with the UK government that would allow his company to run the London Gateway port.

In a previously-unreported email from October 2009, Epstein tells Lord Mandelson, who was business secretary at the time, to "be nice to Sultan".

Email chains also indicate there was a meeting set up between Sulayem and Lord Mandelson weeks earlier to persuade the UK government to support the DP World deal.

The documents also indicate Epstein had helped Sulayem draft a letter to Lord Mandelson and shared the business secretary's personal email address.

It is not clear from the documents whether Epstein's intervention played any role in the eventual approval of the project. But the exchanges appear to suggest that Epstein was acting as an informal intermediary between Sulayem and senior political figures.

There is no suggestion of any wrongdoing by Lord Mandelson in relation to the matter. The BBC has contacted him for his comments.

In a later email, from March 2016, Sulayem tells Epstein he received Prince William at the London Gateway port, and the following day attended a function with him at Buckingham Palace. The emails show Epstein replied with the word "fun".

Other introductions

The documents include emails indicating Epstein introduced Sulayem to international figures from politics and business by email, including former Israeli prime minister Ehud Barak and former Donald Trump adviser Steve Bannon.

Subsequent correspondence shows Sulayem and those figures communicating directly via emails while copying Epstein or forwarding messages to him.

An email purportedly sent from Sulayem in 2015 also inquired about if Epstein mentioned his "proposal" to Elon Musk. It did not provide further details.

The disgraced US financier also offered introductions to the African presidents of Kenya, Senegal, Gabon, and DR Congo. It is not clear from the documents seen by the BBC if this offer was taken up.

Sulayem also apparently sought Epstein's counsel in 2017 regarding an invitation to Trump's presidential inauguration. In the correspondence, Sultan asked, "Should I accept the invitation," before inquiring whether it would be possible to "shake hand with Trump".

In an email in 2013, Sulayem tells Epstein he has been invited by the then-Prince Andrew to lunch at a function he is holding for the president of the UAE who was on an official visit.

Several emails show discussions about plans for Sulayem to visit Epstein's home in New York or his island in the US Virgin Islands. They also regularly updated each other on their international travel plans.