Your editorial of 2 December ('Statistics to count on') claims, "The figures for people leaving the UK are based on a very limited snapshot survey of airport passengers; scandalously, Britain does not count people departing." This is misleading - the International Passenger Survey (IPS) conducts around 700,000 interviews a year at airports and seaports throughout the UK, as well as at the Channel Tunnel terminal, and this is a robust enough sample size to produce accurate data. Interviews are conducted with both arriving and departing passengers.

The Office for National Statistics is working hard to develop new ways of measuring migration as the UK changes, but the IPS remains a reliable measure of migration on a national basis.

Yours faithfully,

Jay Lindop, Deputy Director for Population, Office for National Statistics