To ask the Secretary of State for Transport, what estimate his Department has made of the number of road accident casualties that have been (a) seriously and (b) slightly injured that have been unreported to the police in each of the last three years.

The below table shows the best estimate of the number of road accident casualties in Great Britain that have been (a) seriously and (b) slightly injured that have been unreported to the police for the last three years.

Thousands of casualties (estimates rounded to the nearest 10 thousand)

The unreported road casualties are based on questions asked in the National Travel Survey (NTS) which are based on a sample survey and are subject to uncertainty resulting from small sample sizes. The estimates are created from data collected from the NTS over five years to produce a robust statistic. All estimates are rounded to the nearest ten thousand to reflect the uncertainty.

As the total number of road accident casualties is subject to considerable uncertainty, the lower and upper estimates provided above indicate the range in which the precise number of unreported casualties is likely to fall.

All of the changes between the years are within the upper and lower estimate range. This indicates that the apparent changes are as a result of sampling error rather than a change in the number of casualties.

These figures are also available within table RAS54004.