Britain's rail network has become safer since privatisation, a leading statistician and academic has said.
Christian Wolmer says privatisation contributed to the Hatfield crash
About 150 people have probably lived who might have been expected to die in crashes had pre-privatisation trends continued, said Professor Andrew Evans.
He said accidents had fallen under British Rail but that they had fallen faster, for most accident types, since the network was broken up.
But rail analyst Christian Wolmer said the sell-off contributed to crashes.
He cited accidents such as the Hatfield crash of October 2000 as evidence of this.
Prof Evans, Professor of Risk Management at Imperial College, said it was hard to argue that British Rail would have been safer had it continued in state ownership.
"If you look at the statistics for train accidents over a long period you find that the number per train kilometre, that's allowing for the scale of activity on the railways, has fallen more or less continuously," he told BBC Radio 4's More Or Less programme.
Personal accidents on the railways
"If you take the continuation of that improving trend as the yardstick by which to judge the performance of the privatised railway, in other words if you imagine BR had continued with its improvement, you would have expected more accidents than have actually happened."
But Mr Wolmer said the effects of rail privatisation contributed to the Ladbroke Grove and Hatfield crashes.
"The most obvious one is Hatfield where it really was a lack of communication between the engineering company and Railtrack which led to the rail not being repaired and indeed the judge in the subsequent case commented on that," he noted.
"I would argue that there is no way of proving whether the trend of improvement would have accelerated or decelerated had BR continued.
"Indeed there is some suggestion it would have accelerated over time because of technology improving, because of public demands for more money to be spent on safety."
Although privatisation could well have caused those accidents, others might have been prevented by the change of ownership, Prof Evans maintained.
"I think it is perfectly plausible those particular accidents would not have happened if privatisation had not happened but also to say there are fewer than we would have expected.
"My sense is that the train operators are very much more conscious of safety than probably British Rail operating divisions would have been where it would have been a much more headquarters function than it is now.
"It has been brought home to people on the ground because they are legally responsible."
Find out more by listening to BBC Radio 4's More or Less on Monday 30 April at 1630BST. Click here to listen to the programme.