By CNN Staff
LONDON (CNN) -- The funeral of Britain's first female prime minister, Margaret Thatcher, is under way at St Paul's Cathedral in London.
A horse-drawn carriage earlier carried Thatcher's coffin through the heart of the British capital on a procession route lined with British Army, Royal Navy and Royal Air Force personnel.
Both cheers and boos were heard from bystanders, reflecting the divisive legacy of the politician known as the "Iron Lady."
A single half-muffled bell tolled the arrival of the cortege at St. Paul's and veterans of the Falklands War, alongside members of the regiments associated with the conflict, helped bear Thatcher's coffin into the landmark domed cathedral.
More than 2,000 mourners, including Queen Elizabeth II and serving UK Prime Minister David Cameron, are paying their respects at Thatcher's funeral service.
Thatcher died of a stroke on April 8. She has been accorded a "ceremonial" style funeral with full military honors, similar to those of Diana, Princess of Wales and the Queen Mother.
As a mark of respect, the chimes of Big Ben, as the bell and clock tower by the Palace of Westminster are commonly known, will be silenced for the duration of the proceedings.
A raft of foreign dignitaries are attending the service, including Canadian Prime Minister Stephen Harper, former U.S. House Speaker Newt Gingrich and F.W. de Klerk, the last apartheid-era president of South Africa.
Former U.S. Vice-President Dick Cheney and former U.S. Secretary of State Henry Kissinger are attending but Nancy Reagan -- the widow of Thatcher's ally and former U.S. President Ronald Reagan -- has sent a representative in her place
Any members of Thatcher's Cabinet who are still living and members of the current UK Cabinet, as well as opposition Labour leader Ed Miliband and other lawmakers, were also invited.
Prime Minister David Cameron is giving a reading at the funeral, in accordance with the wishes of Thatcher, who planned many elements of the service several years ago.
According to the order of service released by St. Paul's, the address will be given by the Bishop of London, the Right Rev. Richard Chartres.
Near the end of the service, voices will rise to the hymn "I Vow To Thee, My Country," also a choice made by Thatcher before her death last week, aged 87.
The funeral has been organized in line with the wishes of Thatcher herself and those of her twin children, Mark and Carol. The service, which is being televized, will be followed by a private cremation.
Thatcher's coffin earlier lay overnight at a chapel at the Palace of Westminster and was taken by hearse to the Church of St. Clement Danes -- the Royal Air Force Chapel -- on the Strand, before being transferred to a gun carriage.
Roads near St. Paul's Cathedral closed and buses were diverted from early Wednesday as part of a large security operation, with more than 4,000 Metropolitan Police officers on duty for the event.
Despite leaving office more than two decades ago, Thatcher's political legacy remains divisive and the threat of demonstrations -- on top of fears that dissident Irish Republicans may try to act -- heightened security concerns.
Many Britons blame Thatcher for creating soaring unemployment but supporters believe the tough reforms she pushed through transformed the British economy.
By 8:30am local time, supporters had crowded by the railings of the cathedral, some with folding chairs, and police stood on every few yards down the road to the cathedral.
At Ludgate Circus, Conservative Party activist Lionel Voke said he credited Thatcher with the success of his business and had traveled from Reading for her funeral.
'We're here out of respect - to us, she was wonderful. I accept that not everyone sees it the same way, but it's the same if Tony Blair died - I wouldn't necessarily come, but I'd expect him to be treated with respect, and I'd want him to rest in peace.'
But protester Hilary Jones said she would be among those turning their backs on Thatcher's funeral cortege.
"She was strident in her beliefs and her beliefs were so at odds to a large chunk of the population," Jones said. "There was nothing for many of us to feel proud of during her time."
Thatcher, who led the Conservative Party from 1975 until she was forced to resign in 1990, remained involved in British politics for the next decade or so. She was named Baroness Thatcher of Kesteven after leaving office and served in the House of Lords.
She retired from public life after a stroke in 2002 and suffered several smaller strokes after that.
™ & © 2013 Cable News Network, Inc., a Time Warner Company. All rights reserved.