- More than 2,000 invitations to Margaret Thatcher's funeral are being sent out
- Former U.S. presidents and Hillary Clinton are among those invited to the service
- Anarchists reportedly plan mass "party" Saturday to celebrate Thatcher's death
- Thatcher was widely admired on the global stage but is a highly polarizing figure in UK politics
All former U.S. presidents, former UK Prime Minister Tony Blair and a raft of global dignitaries are invited to the funeral next Wednesday of former British Prime Minister Margaret Thatcher, Downing Street said Thursday.
The guest list also includes representatives of the Reagan family, Nelson Mandela's family and former U.S. Secretary of State Hillary Clinton, alongside sitting British Prime Minister David Cameron.
Any members of Thatcher's Cabinet who are still alive and members of the current UK Cabinet, as well as opposition Labour leader Ed Miliband, will also be asked to attend, Cameron's office said.
Among those expected to come are F.W. de Klerk, the last apartheid-era president of South Africa, Canadian Prime Minister Stephen Harper and one of his predecessors, Brian Mulroney.
Buckingham Palace has already confirmed that Queen Elizabeth II and her husband, Prince Philip, will be present.
With full military honors, the funeral will rival those given to Diana, Princess of Wales and the Queen Mother.
More than 2,000 invitations -- color-coded to indicate where the guests are to sit -- are being sent out, Cameron's office said. They are due to be mailed Friday.
Details of the very formal dress code will be sent out with the invitations.
St. Paul's Cathedral holds 2,300 people and is expected to be full on the day, Cameron's office said.
Some friends of Thatcher have already said they will be absent.
Former Soviet leader Mikhail Gorbachev is not planning to attend for health reasons, Vladimir Polyakov at the Gorbachev Foundation in Moscow told CNN.
Nancy Reagan, the widow of former U.S. President Ronald Reagan, Thatcher's great political friend and ally, is also unable to attend, a spokeswoman said.
"Mrs. Reagan is heartbroken over Baroness Thatcher's death and would really like to be there in person to pay her respects. Unfortunately, she is no longer able to make that kind of a trip so will not be attending the funeral," she said.
Nancy Reagan has asked Fred Ryan, chairman of the Ronald Reagan Presidential Foundation and a longtime personal friend, to represent her at the service.
Downing Street confirmed that the Argentine ambassador to London had been invited, as have other envoys, in line with protocol. No other Argentine representatives have been invited, however, meaning President Cristina Fernandez de Kirchner will not be there.
Fernandez has stepped up her rhetoric in recent months over the disputed Falkland Islands, known to Argentines as Las Malvinas.
Thatcher waged a short, sharp war with Argentina over the Falklands in 1982 after Argentine forces invaded. The islands, which raise their own taxes but rely on the United Kingdom for defense and foreign policy, have been under British rule since 1833.
Thatcher, who led the Conservative Party from 1975 to 1990 and was prime minister for 11 years, died of a stroke Monday at age 87.
A towering figure in postwar British and global politics, she is remembered in the world for her Cold War-era friendships with Reagan and Gorbachev, as well as her role in shaping Britain's place in Europe and her leadership during the Falklands War.
She was on the wrong side of history when it came to South Africa, however, having opposed economic sanctions against the apartheid regime and described Mandela's Africa National Congress as a terrorist organization.
Mandela and de Klerk jointly won the Nobel Peace Prize in 1993 for their efforts to end apartheid.
Back at home, Thatcher was a highly polarizing figure in British politics.
Police are stepping up security ahead of the funeral, amid concerns that protesters angered by Thatcher's actions in office may take to the streets.
Many Britons blame her for creating soaring unemployment, when she reduced or eliminated many government subsidies to businesses and took on unions. Her battle with striking coal miners won her few friends in mining communities in northern England and Wales.
But supporters believe the tough reforms she pushed through transformed the British economy and gave many working people new freedoms.
London's Metropolitan Police, the City of London Police, who cover the city's financial district, and the British Transport Police are working together "to ensure that events that day pass off safely," a statement said.
Police officers will be deployed along the route, with other mobile groups ready to be deployed to any outbreaks of trouble, the Met Police said.
The force has urged anyone planning protests to let police know ahead of time.
"There has been much speculation about what levels of protest may take place. I would ask anyone who wishes to demonstrate then, or in the coming days, to come and talk to us," Commander Christine Jones said.
"The right to protest is one that must be upheld. However, we will work to do that whilst balancing the rights of those who wish to pay their respects and those who wish to travel about London as usual."
Police will implement a range of security measures in line with the current threat level, Jones said.
London's Evening Standard newspaper reported Wednesday that anarchists are planning to stage a mass "party" Saturday in Trafalgar Square to celebrate Thatcher's death.
Ian Bone, founder of the Class War group, is quoted by the newspaper as saying thousands of anti-Thatcher protesters will gather from across the country for the event. They'll include miners and steel workers scarred by her battle with the unions, he said.
Trafalgar Square, in the heart of London, was the scene of violent rioting in 1990 against a hugely unpopular tax brought in by Thatcher. The so-called poll tax was levied on community residents rather than property.
A post on what appears to be Bone's blog also calls on people to attend the "Class War Party" in Trafalgar Square. "Best night out since the poll tax riot," it promises.