Up to one in three British troops involved in the invasion of Iraq last year refused vaccination against anthrax, a newly retired senior officer of the Royal British Legion said yesterday.

Colonel Terry English, the legion's former controller of welfare, revealed the figure when he gave evidence to Lord Lloyd's independent inquiry into veterans' illnesses related to the first Gulf war.

He highlighted what he saw as government failures in the immunisation programme employed before the first Gulf war, and research into the issue.

The cocktail of vaccines, including those against anthrax and plague, administered hurriedly and without adequate keeping of immunisation records, is one of the suggested causes of the high number of veterans reporting sick in the nearly 14 years since the first war.

The MoD's vaccination programme is now clearly voluntary, but it would not comment on the one in three figure for troops who have recently served in Iraq or neighbouring countries, saying that it was an operational matter. If Col English's figure is correct, it would mean that many thousands of the 45,000 troops in Iraq at the height of the 2003 war and the 15,000 that have served there since, refused jabs.