A family’s private grief on this very public day

Sir Mark and Carol Thatcher had ensured the flag-draped coffin was topped with a floral tribute of the purest white roses, bearing the hand-written note “Beloved Mother – Always in our Hearts” from her children.

Both son and daughter were dressed immaculately in black, and looked sombre and often deeply moved throughout the service, pausing afterwards to speak with many of the famous mourners in attendance.

But it was Lady Thatcher’s 19-year-old granddaughter Amanda who took centre stage at St Paul’s.

She made her entrance walking ahead of the coffin alongside her older brother Michael as it entered the cathedral, both carrying cushions bearing her insignia of the Order of the Garter and Order of Merit.

Then she stepped forward to deliver the first reading – a fiery passage from Ephesians 6 which had been chosen by Lady Thatcher herself.

The college student was poised and self-assured as she delivered a flawless reading before onlookers including the Queen and leading politicians and foreign dignitaries as well as millions more watching around the world.

“Put on the whole armour of God, that ye may be able to stand against the wiles of the devil,” the teenager declared, her clear American-accented tones ringing out across the vast space.

It was one of only two readings given during the service – the other being delivered by the Prime Minister.

Afterwards, guests and dignitaries were united in their praise.

Dame Mary Archer, wife of former Tory Party chairman Lord Archer, said: “I thought she read absolutely beautifully.

“She has that attractive mid-Atlantic accent. She was splendid.”

Asked about her accomplished display, Miss Thatcher reportedly smiled and said: “It’s sort of in the blood.”

She and her brother had flown into the UK at the weekend from Dallas, Texas, where they live with their mother Diane Beckett, Sir Mark’s first wife.

Lady Thatcher was known to have adored her grandchildren, telling an interviewer some years after she was ousted as Prime Minister: “When my daughter-in-law sends me photographs of the grandchildren... Apart from seeing them in the flesh, that is the greatest pleasure I have in the whole year, far exceeding everything else.”

Hundreds of people on Twitter, the social media website, praised Miss Thatcher’s “captivating” and “pitch perfect” reading.

Tory MP Nigel Evans said: “I thought she was perfect, absolutely superb.

“She knew the eyes of the world were on her. If she had been speaking at just a family funeral, people can break down and cry, but her composure was perfect.”

Miss Thatcher was a talented sportswoman at school, excelling as a runner and a hurdler, and was eventually voted the student “most likely to change the world” by her high school peers.

Last night Ladbrokes were offering odds of 200/1 for her to one day become US President.

Now studying at the University of Richmond in Virginia, she is, like her brother, an evangelical Christian.

Michael, 24, was also an accomplished sportsman at high school, preferring American football. After studying at a Texas university, he went on to work for a Republican-aligned political group.

It was the birth of Michael in 1989 that led to a visibly excited Baroness Thatcher uttering the now famous line “We have become a grandmother” to television cameras outside 10 Downing Street.

Michael and Amanda were born in the US but spent much of their childhood in South Africa.

After Sir Mark was arrested in 2004 for his involvement in an attempted coup in Equatorial Guinea, however, their mother moved back to Dallas with the children but without him.

Sir Mark and Diane later went through an acrimonious divorce, and both remarried.

But the children were cut off from their father, who was barred from entering the US because of his conviction.

At the age of 12, Amanda wrote to President Bush, asking him to intervene.

“You know how you feel about your daughters,” she wrote. “I want my Daddy back in America.”