Sir: My friend Dave Andrews writes shrewdly about the unsolved problems of whether depleted uranium could have been used in Kosovo from high altitudes or within cruise missiles.

He is on much less sure ground when he uses quotations to play down the health risks associated with DU. Most of such reassurances are based on the erroneous extrapolation of data from the huge doses of radiation that caused casualties at Hiroshima and Nagasaki. It is now known that, at much lower doses, unexpected harmful effects appear.

I thank him for raising these issues. They need urgent and public discussion.

PETER LANYON

Leiston, Suffolk