Jehovah's Witnesses have abandoned one of the central canons of their faith and allowed followers to accept blood transfusions.
Leaders of the sect have told its six million members they will no longer face excommunication if they accept a transfusion under life-or-death conditions.
The decision, made at a secret meeting of the movement's 12-member world governing body at its New York headquarters, is being described as its biggest climbdown since sect's prediction of the end of the world failed to materialise in 1975.
Jehovah's Witness leaders described the change as a "slight adjustment". It follows years of negative publicity about followers of the movement, including children, who have died or come close to death because of their refusal to accept a transfusion.
Only last week, Brent Bond, a Witness from Nottingham, renounced his faith seconds before he lost consciousness so he could receive a lifesaving blood transfusion after losing five pints in a machete attack.
In January, Beverly Matthews, 33, of Stockton, died after refusing an emergency transfusion. Letters have been sent to lead-ers of the sect throughout Britain, where there are 130,000 Witnesses, instructing them no longer to expel members who accept blood.
Jehovah's Witnesses have until now interpreted certain passages in the Bible as meaning they cannot accept any form of transfusion of blood, which they regard as a gift from God.
Geoffrey Unwin, a former Witness who now writes on religion, predicted a backlash from members who had been excommunicated over the issue. He said he knew of at least two who were considering legal action.