At the time , the IRA was targeting trains in London . On 13 February 1976 , a 20 lb bomb at Oxford Circus tube station was safely defused . Eleven days after Cannon Street , a 5 lb bomb prematurely detonated in a train at West Ham station . The next day , one man was injured in a tube train blast at Wood Green tube station
prematurely detonated in a train
West Ham station attack
Cannon Street train bombing