London (AP) — Britain's Iron Lady was being laid to rest Wednesday with a level of pomp and protest reflecting her status as a commanding, polarizing political figure.

A coffin containing the body of former Prime Minister Margaret Thatcher was driven from the Houses of Parliament to the church of St. Clement Danes for prayers ahead of the former leader's full funeral at St. Paul's Cathedral.

From there the coffin — draped in a Union flag and topped with white roses and a note from her children reading "Beloved mother, always in our hearts" — was borne on a gun carriage drawn by six black horses of the Royal Horse Artillery to the cathedral, where 2,300 invited mourners awaited.

Spectators lining the route broke into applause — and scattered boos — as the carriage, escorted by young soldiers, sailors and airmen, passed by.

Some staged silent protests by turning their backs upon the coffin. One man held a banner declaring "Rest in shame." Along the route, arguments broke out in the crowd between Thatcher supporters and opponents.

An honor guard of soldiers in scarlet tunics and bearskin hats saluted the coffin as it approached the cathedral, while red-coated veterans known as Chelsea Pensioners stood to attention on the steps.

Queen Elizabeth II and her husband Prince Philip arrived last among the mourners inside the cathedral, who included dignitaries from around the world, 11 prime ministers and former U.S. Secretary of States Henry Kissinger and George Schultz.

Dozens of people camped out overnight near the 17th-century cathedral in hopes of catching a glimpse of Thatcher's flag-draped coffin and its military escort, and hundreds had arrived hours before the funeral.

"I came to commemorate the greatest hero of our modern age," said 25-year-old Anthony Boutall, clutching a blue rose. "She took a nation on its knees and breathed new life into it."

Flags on government buildings were lowered to half-staff across the country but not all Britons were joining the mourning.

"Like anyone else she deserves a decent funeral, but not at the expense of the taxpayer," said protester Patricia Welsh, 69.

More than 700 soldiers, sailors and air force personnel lined the route to the cathedral and around 4,000 police officers were on duty. Security was stepped up after Monday's bombings at the Boston Marathon that killed three people and wounded more than 170.

Parliament's Big Ben bell was silenced for the funeral service, which was to include hymns and passages from the Bible read by Prime Minister David Cameron and the late premier's granddaughter, Amanda Thatcher.

The woman nicknamed the Iron Lady transformed Britain during her 11-year tenure from 1979 to 1990, privatizing state industries, deregulating the economy, and causing upheaval whose impact is still felt. She died on April 8 at age 87.

Thatcher was given a ceremonial funeral with military honors — not officially a state funeral, which requires a vote in Parliament. Still, the proceedings will feature the same level of pomp and honor afforded Princess Diana in 1997 and the Queen Mother Elizabeth in 2002.

That has raised the ire of some Britons, those who believe her legacy is a socially and economically divided nation.

Retired teacher Henry Page stood outside the cathedral Wednesday bearing a sign protesting the funeral's reported $15 million cost — "Over 10 million pounds of our money for a Tory funeral!"

Cameron insisted the ceremony was "a fitting tribute to a great prime minister respected around the world."

The dean of St. Paul's, David Ison, has acknowledged the funeral has divided opinion, but said the service itself would be a somber affair.

"There is no tribute," he said. "There is no eulogy, and that was Mrs. Thatcher's decision. It's not being triumphalist. It's not a celebration of her life and her achievements."

Some high profile guests sent their regrets, including former U.S. first lady Nancy Reagan — whose husband Ronald had a close relationship with Thatcher — and former Soviet leader Mikhail Gorbachev, who shared key moments in history with the late prime minister. Germany's Angela Merkel sent her foreign minister, while from the U.S., the Clintons and the Bushes declined to attend.

Alicia Castro, Argentina's ambassador to the U.K., also declined. Thatcher went to war in 1982 to retake the Falkland Islands after Argentina invaded the remote British territory off the South American coast.