 Although they had the advantage in numbers , the French were under the impression that they were facing a superior force . Having been mauled by Barnard 's and Bushe 's light companies , and now facing the rolling volleys of the main British line , the French needed time to form from column into line themselves . However , Wheatley attacked as soon as the light companies cleared the field , and only one of Leval 's battalions was able to even partially redeploy . The first French column Wheatley engaged broke after a single British volley . The 8th Ligne , part of this column , suffered about 50 percent casualties and lost its eagle . The capture of the eagle — the first to be won in battle by British forces in the Peninsular wars — cost Ensign Keogh of the 87th his life and was finally secured by Sergeant Patrick Masterson ( or Masterman , depending on source ) . As Wheatley 's brigade moved forward , it encountered the only French battalion , from the 54th Ligne , that had begun to form line . It took three charges to break this battalion , which eventually fled towards the right where it encountered the remainder of Leval 's fleeing division . 
