A man has died just a few yards from an entrance to the Houses of Parliament.
Police and paramedics were called after 7am today to the scene at Westminster Tube station in central London.
The man was found unresponsive, and later died, in an area of the underpass where rough sleepers often spend the night.
Police and paramedics have not yet confirmed the man’s identity, or whether he was homeless.
But Labour MP Angela Rayner tweeted: "A homeless man who was seen frequently at the tube entrance to Portcullis House Westminster underground station has been found dead today.
"Whatever the circumstances it’s a terrible tragedy that somebody ends their days like this, the govt must do more to combat homelessness."
Labour MP Neil Coyle, who co-chairs the all-party parliamentary group on homelessness, said he was told that the man was homeless.
He said the man had "died literally on the doorstep of parliament", adding: "We should all be ashamed and examine hard the causes of his death.
"I will be asking the authorities for more information."
Scotland Yard said the death was being treated as unexplained but not suspicious.
A London Ambulance Service spokesman said: "We were called at 7:16am today to Westminster tube station, to reports of a man not breathing.
“We sent a team leader, an advanced paramedic, a cycle responder and two ambulance crews.
“Sadly, despite resuscitation efforts, he died at the scene.”
The man was found a few steps from an underground entrance to the highly-guarded Palace of Westminster.
The door is used heavily by MPs, researchers, journalists and other Parliamentary staff and is monitored by armed police.
Homeless people can often be seen sleeping in the chilly passageway outside the door in the early mornings.
It comes just days after the local Westminster Council asked wealthier residents to pay a voluntary ‘tax’ to help the young, homeless and lonely.
Tory MP Grant Shapps said the man’s death today was "horrendous news", adding: "Homelessness is an issue that requires constant attention.
"Reducing rough sleeping is the mark of a civilised society and we must now get to grips with the issue."
Newspaper seller Kirsten Hurrell said she saw at least 12 paramedics go to the man’s aid. "There were four ambulances, two bicycles and 12 paramedics went down onto the station," she said.
A Met Police spokeswoman said: "Police were called by the London Ambulance Service at 7.17am to reports of an unresponsive male in the underpass of Exit 3 of Westminster Underground Station.
"Officers and the London Ambulance Service attended.
"The man was pronounced dead at the scene at 7.33am.
"At this early stage in the investigation, the death is being treated as unexplained but not suspicious.
"A crime scene is in place and the exit remains closed. A file will be prepared for the coroner."
A British Transport Police spokesman said: "We were called at 7.21am to reports that a man had been found at Westminster Underground station."