Police officers stand outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

Service men rehearse outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

Service men rehearse outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

Service men rehearse outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

Service men rehearse outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

People to attend the funeral of former Prime Minister Margaret Thatcher rehearse outside St Paul's Cathedral in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

People to attend the funeral of former Prime Minister Margaret Thatcher rehearse outside St Paul's Cathedral in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

A police officer stands outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

Service men rehearse outside St Paul's Cathedral ahead of the funeral of former Prime Minister Margaret Thatcher in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)

People to attend the funeral of former Prime Minister Margaret Thatcher rehearse outside St Paul's Cathedral in London, April 16, 2013. A ceremonial funeral service for Lady Thatcher will be held at St Paul's Cathedral in London on Wednesday. (Xinhua/Wang Lili)