Eleven people have been injured in a sword attack at a church in south London. A naked man wielding a 3 ft (91 cm) Samurai sword burst into St Andrew\'s Roman Catholic church in Thornton Heath, Croydon, during Sunday Mass. The man indiscriminately attacked parishioners - injuring four of them critically - before he was overpowered by members of the congregation. Police have said they are holding a 26-year-old local man in custody. Five minutes previously I was singing the psalm - the next thing I was fighting with a sword-wielding madman     Policeman Tom Tracey The attack happened shortly after the 1030 service had started and witnesses said there was screaming and panic when the man - who has not been identified - began slashing at worshippers. Many of the churchgoers ran into the adjoining hall where a children\'s service was being held. \"We were probably 15 minutes into the children\'s liturgy when the door from the church opened and a mass stampede of people came through,\" said Nanette Frederiksson. One parishioner, Bob Wright, attempted to distract the man by thrusting a large crucifix in his face. But it was off-duty policeman Tom Tracey who eventually managed to overpower the attacker with a 5 ft (152 cm) long organ pipe. \"Five minutes previously I was singing the psalm - the next thing I was fighting with a sword-wielding madman,\" he said. The first paramedics to arrive said they were confronted with a scene of \"blood and panic\". Most of the victims were taken to the Mayday hospital in Croydon where a consultant described the stab and slash wounds they had suffered as \"horrific\". Detective Chief Inspector Phil Fitzgerald said he had no idea why the man carried out the attack.