After all the questions in Parliament, the ministerial statement about the circumstances surrounding the non-departure of a press officer and the threat of a motion of censure, suddenly the responsibilities of the Secretary of State for Transport have a direct relevance in the real world.

After all the questions in Parliament, the ministerial statement about the circumstances surrounding the non-departure of a press officer and the threat of a motion of censure, suddenly the responsibilities of the Secretary of State for Transport have a direct relevance in the real world.

Of course it is too early to form any clear view about the causes or the lessons of the fatal derailment of a train at Potters Bar yesterday, in which more have already died than in the Hatfield crash 17 months ago. At this stage, it is more appropriate to express sympathy for the bereaved families and admiration for the work of the emergency services.

However, the potential importance of yesterday's tragedy can be measured by the fact that the Hatfield derailment turned the network into a national go-slow and finished off Railtrack as a company. All the more important, therefore, that there should be no rush to judgement – not least because of the increasingly frequently held view that the Government and Railtrack overreacted to the Hatfield crash.

Whatever Stephen Byers' many weaknesses as a minister, it seems unlikely that he could be held personally responsible for this accident. The fuss over his political future should not be allowed to cloud an appraisal of what happened yesterday. Equally, strongly-held views about the privatisation of the railways or about the re-nationalisation of the track company should not be allowed to influence our assessment.

In addition, there are many reasons for trying, even at this early stage which must be so painful for the families of those who died, to maintain a sense of perspective. It is always worth comparing the overall safety record of modern British railways with the past, with other countries or with other forms of transport. Despite a series of memorable crashes, rail travel in this country has been safer in recent years than it used to be.

Our safety record is also better than that of the railways in Germany, for example, despite that country's reputation for engineering excellence. There have also been at least two serious accidents in the United States recently, which should serve to remind us that no form of travel can ever be made wholly safe. The obvious comparison is with the death toll on the roads – an average of nine people every day of the year.

It is undoubtedly the case that a pile-up on a motorway which killed as many people as died on the train at Potter's Bar yesterday would merit a short news report on the inside pages of most newspapers. We should, however, remember an important difference between road and rail transport: getting on a train, we entrust our lives to the competence and vigilance of strangers. It is for that reason that we expect higher safety standards – and different news values.

A more apposite comparison is that between railways and aeroplanes. Aviation is an intrinsically more dangerous form of travel, yet its safety record is astonishingly good. Regardless of the outcome of any inquiry into the Potters Bar crash – and regardless of whether the railways are within the public sector or the private sector, or both – the really difficult question is always going to be how to replicate the aviation industry's safety culture in the railways.

Ultimately, that is a much more important issue than the future of Stephen Byers as a Cabinet minister or the inevitable, frantic hunt for someone, anyone, to blame.