Meghan Markle’s estranged dad has said he’s prepared to sue his daughter and her husband to gain access to his grandchildren.

Thomas Markle, 77, has yet to meet Archie and Lilibet Mountbatten-Windsor – or even Prince Harry.

The former lighting director told Fox News in an exclusive interview that he is ready to take the matter to court ‘in the very near future’.

He has had a strained relationship with his daughter ever since her wedding to Harry, where Thomas struck a deal with a paparazzi photographer to stage photos of him. He was then forced to pull out of the ceremony – and walking his daughter down the aisle – after health issues, which saw Prince Charles take his place.

But Thomas says his health is continuing to deteriorate and fears he may never get to meet Archie, two, or new-born Lilibet, who was born last month.

Speaking at his home in Rosarito, Mexico, he said: “We shouldn’t be punishing [Lili] for Meghan and Harry’s bad behaviour. Archie and Lili are small children. They’re not politics. They’re not pawns. They’re not part of the game. And they’re also royal and entitled to the same rights as any other royal.”

“I will be petitioning the California courts for the rights to see my grandchildren in the very near future,” he added.

Thomas also slammed Harry’s announcement of the upcoming release of his memoirs in 2022 in the interview. The book, published by Penguin Random House, is expected to cover the “highs and lows, the mistakes, the lessons learned” of his life.

But Thomas suggested that “after three sessions with the psychiatrists and Oprah Winfrey”, the Prince would not “have too much more to tell”.

The grandad has been highly critical of the Duke and Duchess of Sussex following the bombshell interview with Oprah earlier this year, in which Meghan said her dad had “betrayed” her and she “found it hard to reconcile” with him.

• Agencies report