Margaret Thatcher worried she had 'failed her children' in old age

Thatcher feared she was a 'successful wife and unsuccessful mother'

Mr Harris said it had in fact been Margaret Thatcher who convinced him to vote Tory in 1987 (Getty Images)

Margaret Thatcher worried she had neglected her children in her final years, her biographer has claimed.

The journalist Charles Moore spent long periods of time interviewing the first and only female Prime Minister after he was chosen as her official biographer.

Moore, who developed a relationship with Baroness Thatcher over the course of 18 years, also interviewed 286 people for the final volume of his forthcoming biography, which has yet to be published.

Thatcher was elected as Prime Minister three times and had two children, Carol and Mark Thatcher, who were adults when she began her first term in office.

“In old age she had regrets about private things,” Mr Moore told The Times. “About whether she had failed her children.”

Carol, a journalist and broadcaster, described how her 'superwoman' mother balanced a career in politics with a domestic life in 2013.

“She was always flat out, she never relaxed, household chores were done at breakneck speed in order to get back to the parliamentary correspondence or get on with making up a speech, she told the BBC.

Mr Moore claimed she also feared she had spent time at home with her family thinking about other matters, describing her as “a successful wife and an unsuccessful mother”.

Born in Grantham to a grocery shop owner, Thatcher went on to become a formidable and devisive Prime Minister, earning the nickname the ‘Iron Lady’ and a reputation for refusing to yeild in almost any circumstance. She died in 2003 from a stroke after suffering from dementia and years of poor health.