It was in July 1989 that Mr Magill received objections from Westminster's Labour group and, using powers available to him under the Local Government Finance Act, began to investigate allegations that the Tory-controlled council operated a covert housing scheme.
Now he has verified that "gerrymandering" took place, the controversy will move to the High Court.
The bitter contest will feature John Magill v Dame Shirley Porter et al.
Speaking near Dr Johnson's old London house yesterday, Dame Shirley said that she was confident of winning "when the evidence and case is heard by a judge".
Sources close to Dame Shirley have said that even if the High Court does not deliver, the fight will go on - to the Court of Appeal and the House of Lords if necessary. The European Court of Human Rights is another likely venue in future.
Today, Mr Magill will begin the process of choosing his legal team for the High Court hearing. A team to match the high-powered talent representing Dame Shirley will not come cheaply. The Magill audit has cost the ratepayers of Westminster pounds 3m and they will continue to pay for the legal tussle ahead.
If the case lasts another decade - and it easily could - the final bill may reach pounds 5m.
That might only be the first installment. In addition to the "designated sales" objections, Labour has also lodged complaints over alleged abuses of planning during the Tory administration of the Eighties, their environmental policy, the way key wards were targeted with public relations material and the disposal of property below its market value to achieve political aims.
This list, in conjunction with the published report on the absence of repair bills for key leaseholders, the scandal over asbestos in Westminster Council properties, and even the furore over cemetery sales, could mean that yesterday's surcharge announcement is merely the opening chapter of a very long book.
Melvyn Caplan, the current Conservative leader of Westminster Council, says of Labour's attacks on his party: "They have a strategy of objecting to everything. This year they objected to the level of council tax."
Mr Caplan now hopes that the legal struggle in the High Court will act as a test case for the way councils are investigated in the future. "Today we saw six people receive a bill. However, countless others have been investigated and have had to pay their own legal bills only to be cleared," he said.
"That is the reverse of our legal principle. Under the current system you are guilty till you pay to prove yourself innocent."
And the cost of the audit? "So far every resident of Westminster has contributed pounds 30 each to the bills we have received from Mr Magill," added Mr Caplan. "That amount will increase."Reuse content