Why Meghan Markle's father will likely never meet his grandchild

New claims about the Duchess of Sussex, left, with her husband Prince Harry, have been made in a documentary. Photo / Getty Images

The bitter split between the Duchess of Sussex and her estranged father Thomas Markle has taken another sad turn in an explosive new documentary.

In Meghan and Harry: A Royal Baby Story, a royal author suggests Meghan Markle's father will never meet his grandchild.

"I can't think for a moment that Thomas Markle will ever be able to meet his grandson or granddaughter," royal biographer Duncan Larcombe said.

Thomas Markle, 73, who was busted for selling stories to the press including set-up paparazzi shots, has not spoken to his daughter, 37, since last year, when he missed her wedding to Prince Harry.

Meghan is due to give birth to her first child to husband Prince Harry this month.

The documentary - set to air in the UK on April 9 - also features an interview with Meghan's half-sister Samantha Markle, 54, who accuses her former Hollywood actor sister of "hurting the family".

"You can't hurt people like this and then turn around and flip the script and play victim," Samantha said in the new footage, according to the Daily Mail.

The former Suits star is expecting her first child to husband Prince Harry later this month. Photo / Getty Images

Despite Meghan's silence, the issues within the Markle family have long been played out in the media.

In February, a letter sent from the Duchess of Sussex to her father was made public, in which she begged him to leave her in peace.

Thomas said the handwritten letter was "a dagger to the heart" which left him "devastated".

In it, Meghan accused her father of breaking her heart "into a million pieces" by allegedly lying in the press and publicly attacking her husband Prince Harry.

"I begged you to accept help - we sent someone to your home … and instead of speaking to me to accept this or any help, you stopped answering your phone and chose to only speak to tabloids," she wrote.

"If you love me, as you tell the press you do, please stop. Please allow us to live our lives in peace."