A man is in a coma after being found lying unconscious with severe head injuries in the Hyde Park Corner underpass.
John Bryson was discovered by a member of the public at around 8.25am on Saturday November 11, who called London Ambulance Service .
The 48-year-old was taken to hospital where police were alerted to his condition and consequently launched an investigation.
He remains in a serious condition in hospital with potentially life-threatening and/or life-changing head injuries.
His next of kin have been informed.
"While we have already conducted extensive enquiries, we would like to speak to anyone who knows Mr Bryson or has any information about his movements on or prior to the November 11," said Detective Constable Chris Smither of Westminster CID.
"Mr Bryson is lying in a coma in the hospital in a very serious condition therefore we would urge you to contact us, any information will be treated in the strictest of confidence."
Police are appealing for information about his movements during the 48 hours leading up to the attack.
Officers say he was believed to be rough sleeping at the time of the incident, and because of his condition, has so far been unable to assist officers with the investigation.
Anyone with information is asked to call police on 101. Those wishing to remain anonymous should contact Crimestoppers on 0800 555 111.
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