It is very worrying that children as young as four years old are reported to be playing on railway lines in the Bradford area. Their parents are behaving irresponsibly both towards their children and to society in general by failing to keep an eye on them.

No doubt some of them will have been in the care of older siblings. However, that is no excuse. No child of four, or even several years older, should be able to roam about freely and unsupervised by an adult.

To let them do so is to put them at great risk. As Inspector Cameron Young of the British Transport Police rightly says, it is important that parents stay aware of where their children are and what they are getting up to.

Apart from the obvious dangers to the children themselves of playing on railway lines, there is the chance that they could be tempted into causing damage to track and trains.

There have been many cases reported this year of obstacles being placed on the track. In two of them, trains actually collided with objects placed there by youngsters. There is also the problem of stones being thrown at trains.

The spate of summer incidents should tail off in a couple of weeks when the children return to school and the evenings grow shorter.

However, it will be back again during the next holiday unless parents start to behave responsibly and make sure that at all times they know where their children are and what they are doing.