The Metropolitan Police has referred itself to the police watchdog over a 2019 letter it passed to Meghan Markle about her father.

The force handed a letter containing accusations against Thomas Markle Sr, 82, to the Sussexes in 2019, which contained 'a number of claims about alleged offending outside the United Kingdom'.

But it failed to pass on the letter, or details of the alleged offences, to any other law enforcement agencies, and did not launch a probe into Markle Sr themselves. 

The Met has today referred itself to the Independent Office for Police Conduct (IOPC) over its handling of the letter, and said it does now intend to make 'a number of referrals to relevant overseas law enforcement agencies' in relation to the claims set out within it.

It's understood the letter was written by Markle Sr's late first wife, Roslyn Loveless, and contained 'troubling and disturbing' allegations against the Duchess of Sussex's father.

Last week it emerged Meghan was allegedly informed the allegations raised in the letter were being investigated. 

It comes after Meghan's half-brother, Thomas Markle Jr, 60, claimed last week he had discovered a trove of child sex abuse images in his father's possessions at his home in the Philippines. 

Markle Sr is accused of having a 'sickening' collection of child abuse images, including videos of girls no older than ten or 11 involved in sex acts. 

Thomas Jr claims to have found the material while looking through his father's boxes in July this year to find a phone for his fiancée, Rose, after his father had returned to the US for medical treatment. 

He allegedly also found a 15-minute video of naked girls on his father's old phone, and 'hundreds' of indecent images including pictures depicting children as young as toddlers.

Authorities in the Philippines have launched a probe and were handed a warrant by a court today allowing them to examine the digital material handed to them by Thomas Jr. The FBI are also said to be poised to join the investigation. 

Announcing the referral to the IOPC today, Commander Adam Slonecki, who leads the Metropolitan Police's Protection Command, said: 'In January 2019, the Met received a letter addressed to our Protection Command, specifically the Fixated Threats Assessment Centre.

'The author of the letter suggested they were writing to raise concerns relating to the security of the Duchess of Sussex. While the letter did not actually contain any information specifically related to security matters, it did contain a number of claims about alleged offending outside the United Kingdom.

'The letter was assessed and subsequently passed to the office of the Duke and Duchess of Sussex for their awareness. The details of the allegations in the letter were not shared with other law enforcement agencies.

'In recent days, the Met's Directorate of Professional Standards has carried out an initial review into our actions following receipt of the letter in 2019.

'Following that review, a voluntary referral has been made to the IOPC in respect of the decision not to inform other law enforcement agencies, and the decision to pass the letter to the office of the Duke and Duchess of Sussex.

'In addition, it is our intention to make a number of referrals to relevant overseas law enforcement agencies in relation to the allegations contained within the letter. That process is underway and will be completed in the coming days.'

Thomas Jr said last week he found 'hundreds' of child sex abuse images in four boxes stored at his father's home in Cebu in the Philippines, which contained multiple digital devices.

One 35mm photograph reportedly shows a bearded man resembling Mr Markle having sex with a young Asian girl. 'I have never been in a photograph like that,' Markle Sr said on Saturday.

Markle Sr denies the allegations, calling them 'sick lies' and says he will do 'whatever it takes' to clear his name. 

He is currently receiving medical treatment in a rehabilitation centre in Florida after having his left leg amputated.

The Duchess of Sussex released a statement last week saying she was first made aware of 'troubling and disturbing' allegations about her father after a letter was passed to her by royal protection officers. She added she was given assurances the claims were being investigated.

'I am deeply distressed at the news that has come to light in the last 24 hours, and my thoughts are with any children who may have been harmed,' she said.

'I hope it can now be understood that, despite certain media publications' distortion over the years, any distance from my father and my choice to not allow him to have contact with our children, was for one reason: to protect them.

'I trusted that the authorities were doing the same for other families.

'Although the breadth of what has now been uncovered is more sickening than one could ever imagine, my sincerest hope is that justice will be fully served and that the priority remains the safety and protection of innocent children.'

Today it was reported a court in the Philippines has issued a warrant allowing police in the country to examine the material passed to them by Thomas Jr.

Philippine interior minister Jonvic Remulla previously said the forensics data is expected to be completed in a week, but 'right now all signs point to a possible sex offender of the grossest kind'. 

Although Meghan became publicly estranged from her father in 2018, prior to her wedding to Prince Harry, she last year sent a letter to him informing him she would never contact him again, and he would not meet his grandchildren. She reportedly said this is due to her, and authorities, knowing he had abused young girls. 

An IOPC spokesman said: 'We have received a voluntary conduct referral from the Met Police, which relates to the handling of a letter it received in 2019 involving allegations of offending. 

'We are now assessing the referral before deciding what further action may be required.'