Students at Birmingham University have banned the National Blood Service from attending their freshers' fair in protest against its policy towards gay men.

The blood donor organisation, which heavily targets university campuses for volunteers, does not allow men who have had sex with men to donate blood.

Birmingham University's Guild of Students accused it of "homophobia" and of treating the gay and lesbian communities as "dirty and second class".

The organisation denied the charge but stood by its policy, claiming research showed there to be a higher risk of the HIV virus in gay men.

Birmingham University's Guild of Students decided to stop the service from attending its freshers' fair later this month in an act of solidarity towards its lesbian, gay, bisexual and transsexual community.

But the National Blood Service last night defended its stance, claiming it was medically motivated and not a "prejudice issue".

Lyndsay Stewart, West Midlands spokeswoman for the NBS, said: "Our most recent research shows the total number of instances of HIV is still higher among the homosexual community. It is a blood safety issue."