A dozen Oxford professors are among 100 top British medical scientists who complain that red tape on animal experiments is holding back vital research.

The group, which includes Professor Colin Blakemore, a long-time defender of the need for animals in research, says the restrictions are allowing other countries to race ahead of the UK. In an open letter to science minister Lord Sainsbury, they demand action from the Home Office over the lengthy delays involved in gaining approval for animal experiments.

Their letter says: "If this situation persists or gets worse, as it has recently, a substantial part of the UK's research effort in many vital areas will either become un competitive or be forced abroad." The scientists' move brought swift condemnation from the British Union for the Abolition of Vivisection.

Chief executive Michelle Thew said she was "amazed and outraged" at their claims.

Prof Blakemore was sent a letter bomb by animal welfare activists in 1998.