By Brian Wheeler
BBC News political reporter, at the Royal Courts of Justice
If Stephen Byers was feeling a little anxious as he entered the witness box at the Royal Courts of Justice it did not show.
Mr Byers denies deliberately allowing the firm to fail
The former transport secretary is accused of abusing public office by deliberately engineering the collapse of Railtrack without properly compensating shareholders.
It is thought to be the first prosecution for misfeasance of this kind in 200 years - and the first time a secretary of state has been at the centre of such charges.
But Mr Byers appeared calm and relaxed as he sat in the spacious semi-circular witness box in Court 62.
Immaculately dressed in a dark suit and trademark steel-rimmed glasses, he leafed through the court documents and answered the questions posed by Keith Rowley, who is representing 48,810 Railtrack investors, calmly and politely.
He even ventured the odd witticism.
"I have to admit, not the first time in my public life and political life, I don't agree with Clare Short," he said after a 1996 letter by his ex-cabinet colleague was read out to the court detailing the case for renationalising Railtrack.
His demeanour might be explained by the fact that Mr Byers is not facing any charges himself. It is the office of secretary of state that is in the dock not the former cabinet minister.
But they are, as Mr Byers told the court, "very serious allegations", and ones which he says are "without foundation in fact and are simply wrong".
For many of the Railtrack shareholders who had crowded into the tiny court, tucked away on the 11th floor of the Royal Courts, it was a victory just to see the former minister in the dock. There was standing room only.
Thanks to the Freedom of Information Act, the prosecution has had unprecedented access to internal memos and e-mails, allowing Mr Rowley to set out a detailed picture of Mr Byers' first week in office in June 2001.
Like the Hutton inquiry, which was conducted in a similar room at the Royal Courts, with the sun blazing outside, the proceedings provided a rare glimpse into the internal workings of Whitehall.
Mr Rowley attempted to establish that Mr Byers had sought the collapse of Railtrack from the beginning for political reasons, realising how popular it would be with the unions and Labour's backbenchers.
The picture that emerged was of a new cabinet minister under pressure from Mr Blair to sort out Britain's railway system but with no obvious means of making progress.
At the same time, Railtrack's share price had plummeted in the wake of the Hatfield crash and there was a question mark over its financial viability.
Mr Byers was also facing a Treasury reluctant to bail out the ailing company with public money - and unhappy about the powers wielded by rail regulator Tom Winsor.
For added drama, Mr Winsor was watching the proceedings from the public gallery, a few feet to the right of Mr Byers, The former rail regulator remained impassive throughout, even when "TW" was described in the minutes of a meeting as being "idiosyncratic" and pursuing a "vendetta against Railtrack".
The early exchanges centred around whether Mr Byers had been "seriously concerned" or simply "concerned" about the state of Railtrack's finances when he took office.
Mr Byers eventually conceded that he had gone from the former state to the latter in the space of two days, after reading a memo describing the company's financial position as "critical".
The focus then switched to the precise meaning of the term "basket case".
Mr Byers was revealed to have used this term in a meeting to describe Railtrack.
Surely this meant he thought the company was "beyond redemption"?
"Basket case" might have a number of meanings, Mr Byers said.
At the time, the MP was using the east coast mainline to travel to his constituency, and so his personal experiences may have coloured his view, he told the court.
"Basket case is a moderate term. I may have said something else," he added.
"If you are saying that, because I referred to Railtrack as a basket case, I had decided to embark on the administration plan, then you are simply wrong."
Mr Byers, as the court was reminded at the start of the proceedings, is a lawyer by training, and he was not going to let any point go without a fight, even quibbling at one point about the description of the material Mr Rowley was reading out to him as "minutes".
"They are not really minutes they are action notes. They are being sent out to tell civil servants what needs to be done," said Mr Byers.
Commenting on Mr Byers' performance outside, one Railtrack shareholder, who did not want to be named, said: "He's an old smoothy isn't he? But the juicy stuff is still to come."
...The case continues.