West Ham’s persistent conceding from corners stems from opposing set-piece tactics: use of ‘blockers’ to impede the goalkeeper, crowding the six-yard box, far-post overloads, looping crosses and screening to free attackers. BBC analysis cites Chelsea (Liam Delap vs Hermansen), Spurs (far-post for Pape Matar Sarr) and Crystal Palace (Mateta/Guehi routine) and urges fixing set-piece frailties.