This woman's army: dress rehearsal for Baroness Thatcher's funeral tomorrow John Stillwell/PA
The limits of peaceful protest will be tested at tomorrow's ceremonial funeral for Margaret Thatcher. The former prime minister had meticulously planned the event in advance. But it is not known whether she factored in the thousands of people who say they will protest as her flag-draped coffin makes its way through the streets of London.
The Met Police, already grappling with the security headache of having the Queen and hundreds of VIPs all gathered in one place, have found themselves caught up in a row about the right to freedom of expression.
More than 700 Royal Navy, Army and RAF personnel will line the three-mile route of the funeral procession from the Palace of Westminster to St Paul's. Tens of thousands are expected to turn out to pay their respects.
Police have the power to make arrests even against non-violent actions if they judge they could cause "harassment, alarm or distress" to mourners.
On the other hand, the officer in charge of the 4,000-strong police operation has said her job is not to ensure that respect is shown, merely that the law is upheld.
A poorly attended 'death-party' in a damp Trafalgar Square on Saturday night saw scuffles between police and the 1,000-strong crowd, so Scotland Yard is likely to be fully prepared for any disorder.
Online chatter about former miners planning to throw lumps of coal at the cortege seems far-fetched. A plan by others to turn their backs as the procession passes has been approved by police. But before the pomp, there will be a ceremony for Lady Thatcher today, when her body arrives at the Palace of Westminster.
A short service in the chapel of St Mary Undercroft will allow MPs, peers and staff to pay their respects. The body will remain at Westminster overnight.
Lady Thatcher's ceremonial funeral may have seemed like a good idea when she planned it, but a state-funded event for such a divisive figure was always going to cause problems.
There are questions over the cost of the funeral – estimates range between £5m and £10m.
The Commons will not sit until after the funeral service has ended, meaning that Prime Minister's Questions has been cancelled.
Privately, unhappy MPs question if it was really necessary to recall parliament last week.
The announcement that Big Ben will be silenced during the funeral also raised eyebrows.
Whatever politicians at Westminster think, the reactions of the crowds in London tomorrow will determine if the decision to grant Lady Thatcher a funeral on a par with Diana and the Queen Mother was the correct one.