Dr Hildyard's letter criticising Floodline was unjustified (What good is the Floodline?, January 24).

Flood forecasting will never be a precise science, but when the high water reaches Moor Monkton, we can give a very accurate prediction of the peak level expected in York. However, this can only be about six hours in advance, which doesn't give people time to prepare for the worst.

This is why we also try to predict York's peak levels 36 hours earlier, but accuracy is impossible so far ahead, especially if rain is falling and river levels are rising. Last week's early predictions indicated a possible high water level similar to November 2000's widespread flooding. Our experience suggested this was unlikely, so we decided not to issue warnings and cause unnecessary alarm.

We monitored the situation very closely. By Tuesday morning (January 22) the situation was clearer and we publicly predicted a high water level up to 4.7 metres above normal later in the evening. York Flood Group met at 2pm, when our best estimate was that the level would be around 4.5 metres. The multi-agency response was based on this.

The peak level was 4.473 metres above normal at 3.45am on Wednesday. Floodline was used to give out this information.

It is simply impossible for us to give an accurate prediction of final water levels in York more than 24 hours before the peak. Flood Warnings are only issued when we believe there is a high probability that properties will be flooded and people need to act.

Floodline is a national service and is the most dialled telephone number after 999. Between Friday, January 11 and Friday, January 25 there were 86,702 calls to Floodline's recorded message service and 14,633 calls to its call centre.

I hope this explanation will reassure your readers that while flood prediction is not a precise science, York has one of the best systems possible and its multi-agency response is exemplary.

Colin Atkinson, Flood incident management team leader, Environment Agency, Coverdale House, York.