Whilst Prescott may have spoken in favour of, and instituted, a tougher regulatory regime, he did not cause the Southall, Ladbroke Grove, Hatfield and Potters Bar accidents, and he wasn't responsible for the decision by the directors of Railtrack after Hatfield, to order extensive checks as they weren't confident about the state of the rest of the network, or the delay compensation that thus ensued.
And Prescott absolutely certainly was not responsible for the decision by the company to use money it begged from the government to help with its losses to controversially pay shareholders a special dividend.
From https://en.m.wikipedia.org/wiki/Railtrack
It was the Hatfield crash on 17 October 2000 that proved to be the defining moment in Railtrack's collapse.[12] The subsequent major repairs undertaken across the whole British rail network are estimated to have cost in the order of £580 million. According to Christian Wolmar, author of On the Wrong Line, the Railtrack board panicked in the wake of Hatfield.[13] Because most of the engineering skill of British Rail had been sold off into the maintenance and renewal companies, Railtrack had no idea how many Hatfields were waiting to happen, nor did they have any way of assessing the consequence of the speed restrictions they were ordering – restrictions that brought the railway network to all but a standstill.[14]
Regulatory and customer pressure had been increasing, and the company's share price began to fall sharply as it became apparent that there were serious shortcomings in the company's ability to tackle and solve its greatest problems.[15]
Although it can sound like it, this isn't about the philosophy or politics of private versus public sectors. In the limit it's about having something that pragmatically works, instead of incompetence caused by bad organisation.
On electricity privatisation, the other companies effectively got National Grid for free, then reorganised and floated it off separately. After rail privatisation, it is rumoured the various companies had more contract lawyers than engineers.