Man critical after fight on Westminster Bridge
· BBC NewsA man is in a critical condition in hospital being treated for a heart attack after a fight broke out on Westminster Bridge, the Met Police said.
London Ambulance Service and the air ambulance took him to hospital after a call was made to emergency services at about 10:45 GMT.
Initially he was thought to have been stabbed, but the Met Police said further enquiries had confirmed this was not the case and that officers were investigating how he came to have a cardiac arrest.
Three people have been arrested on suspicion of attempted murder while another arrested for affray, the Met added.
Two of those arrested have been taken to hospital with head injuries.
The force has urged any one with footage, either from CCTV, mobile phone or dashcam, to contact them.
It said officers were "particularly keen to hear from anyone who was in the area at the time and may have witnessed the incident".
The bridge, which was closed for several hours while investigations were carried out, has now reopened.