Many Sites of Special Scientific Interest are on ministry land and hunting is permitted across 18 of them. Twenty-three packs have been granted licences to hunt on MoD land during the current season. Sites of Special Scientific Interest are designated to protect rare species and environments.
According to the League Against Cruel Sports and Alan Meale, Labour MP for Mansfield, who carried out the research, 10 of the SSSIs to be hunted are in the Otterburn Training Area in Northumberland. The sites include Linbrigg, a refuge for Jacob's ladder, a rare flowering plant; Barrow Burn, a meadow rich in rare species; and Durtrees Burn, a streamside meadow.
English Nature, which draws up management plans for SSSIs in consultation with landowners, said: ''If a hunt was accompanied by a large number of horses, surface disturbance to sites might occur.''
Mr Meale said: ''How can you justify hunting on these sites when they are clearly intended as nature reserves? It's completely wrong and totally contrary to their spirit.''
A spokesman for the Ministry of Defence defended hunting on nature reserves. He said: ''Hunting is legal and has genuine military training advantages. We have an excellent record in the field of conservation and land owned by the MoD has been incorporated into national parks precisely because it has been looked after and relatively unspoilt.''
Hunting on ministry land is by ''invitation only'' and is at the discretion of the commanding officer.
Commanding officers are responsible for ensuring that the huntsmen abide by hunting codes of practice. Commanding officers are also given the option of charging for licences. In 1992-93 pounds 292.80 was raised nationally and pounds 507.30 in 1993-94. Only 16 of the hunts granted licences for 1994-95 pay for them.
Military police are used to protect huntsmen from any anti-hunt protesters on ministry land. A spokesman for the MoD said that the Military Police would remove trespassers who were ''trying to break up a hunt or any other lawful activity''.
Angela Smith, spokeswoman for the League Against Cruel Sports, said: ''We would like to know what the terms and conditions of the licences are and under what circumstances one could be revoked. We also want to know who's monitoring the hunters to see that the they are abiding by the rules.''