The Army and Royal Air Force has banned personnel attending the Gay Pride parade from marching in uniform.
The Times reports that about 125 servicemen and women have told organisers of the march that they would like to take part.
But the Royal Air Force has said personnel who wear uniform to march in the parade in London this Saturday (30 June) will face disciplinary action.
Last week, the head of the Army issued orders banning soldiers from marching in uniform.
The Royal Navy, which is a member of the Stonewall Diversity Champions good practice scheme, allows sailors to march in uniform and uses it as a recruitment opportunity.
The Ministry of Defence is keen to promote all the armed services as good employers for minority groups, including gay and lesbian staff.
