A bloodied stab victim in his 60s staggered inside the Home Office for help today after being knifed in an 'unprovoked' attack outside the building in Westminster.

Dramatic photographs showed the victim 'full of blood' being led away by police and paramedics this afternoon from the site, which was put into lockdown.

The victim was taken to a major trauma centre, and witnesses said they saw another man putting something into his bag before walking 'calmly' down the road.

Scotland Yard officers arrested a 29-year-old man on suspicion of grievous bodily harm and possession of CS spray before taking him to a police station.

Police said they were not ruling out terror as a motive, following unconfirmed reports that the victim was an employee targeted due to him wearing a Home Office pass.

It comes just days after Home Secretary Priti Patel, who has an office in the building, gave police increased powers for stop-and-search amid a knife crime epidemic.

An injured man is helped by a medic and police outside the Home Office in London today

Police said the injuries suffered by the man are 'currently being treated as life threatening'

Scotland Yard said 'enquiries are ongoing into the exact circumstances of the incident'

Police investigate outside outside St John's Smith Square Church after the stabbing today

Pictured: Belongings at the scene in Westminster as forensics analyse items left at the scene

Items including 'self defence' spray, coins, a train ticket from London to Birmingham, keys, a receipt and an Oyster card were seen on the ground behind a cordon.

An office worker opposite the building described seeing a man - thought to be the perpetrator - walk calmly down the road following the incident shortly after 1pm.

She said: 'He was standing over there outside the Home Office and then he was putting something away in his bag, but I didn't see a knife or anything.

** Were you there? Email mark.duell@mailonline.co.uk or call 020 3615 1838 ** Advertisement

'He was putting something away and then he just calmly just walked off down the road as if nothing had happened.

'Then people were being asked to go into the Home Office, they were being ushered in.'

Eyewitness Guy Ellis, 54, described seeing a man remove a 'long' knife from his bag before the incident.

Items including spray, cash, train tickets, keys and an Oyster card are pictured behind a police cordon outside St John's Smith Square Church in Westminster after the incident today

Police are pictured at the scene outside the Home Office in Westminster, central London, as they scour the scene following today's stabbing

'I was sat outside the Home Office waiting for a friend to meet for lunch and on the other side of the entrance I just saw a bloke take a knife out of his bag, and just wander up the path, stop in front of two girls who were just sat there having a chat, and then he wandered back and turned round and crossed the road very calmly and merged into the crowd.'

He said the knife was 'long and thin' and 'pointy', and described the man as 6ft, slim, with long, dark hair in a ponytail and said he was 'scruffily' dressed.

Salvatore D'Auria, 41, manager of a restaurant opposite the building, said: 'There was an old man coming out of the building with police and a paramedic covered with blood. He had his jacket on and it was ripped at the back.

'He was covering his face and blood was on his face. I was right there when I saw the man coming out. He was without a shirt but the jacket was on and ripped.'

Police officers were seen arriving on motorcycles and cars at the scene on Marsham Street, with ambulances and paramedics also in attendance.

Items behind a police cordon including glasses and what appears to be a walkie talkie today

Investigators look at items outside St John's Smith Square Church in Westminster today

Forensics are analysing what appears to be a knife holder at the scene in Westminster today

Detectives examine the crime scene in Smith Square after a knife attack near the Home Office

Witness Gareth Milner said he was eating his lunch on the wall outside the building when 'a number of armed police officers arrived on scene and entered'.

'Some time later a gentleman with quite a bloodied face and with dressing pressed into his face was escorted out of the Home Office by paramedics,' Mr Milner added. 'He was quiet and walking on his own feet, not being physically supported.'

Mr Milner, who works nearby for the Centre for Policy Studies think-tank, said a police officer told him someone had been stabbed, but gave no further details.

Earlier, Mr Milner tweeted: 'Lots of armed police and a cordon going up outside the Home Office. Gentleman with a bloodied face has been led out by paramedics.'

Shaun Malston, 43, a property manager at Garton Jones estate agents opposite the Home Office, described seeing people running into the building after the stabbing.

'I suddenly heard a lot of noise and commotion - people shouting - and people running into the Home Office,' he said.

The stabbing comes after the new Home Secretary Priti Patel (pictured in her first interview in the role on July 26) promised to tackle to scourge of knife crime on London's streets

Police officers arrive outside the Government building on Marsham Street this afternoon

Blood is photographed on the pavement outside the Home Office building this afternoon

'I happened to notice a guy by the tree over there, just sitting to the right of it, and then turned around and was putting something into a backpack.

'A lot of people sit out there during lunch but he was probably one of the few that was left there because everyone else was running away and scattering, and he just put stuff, whatever, into his backpack and put it back on and just walked down (the road).'

He said he saw the victim walking out of the Home Office 'with his shirt off, but he had a jacket on and he had blood all down his chest and he had a patch over his eye'.

A barista working opposite the Home Office said she saw a man 'full of blood' walking out of the Government building.

The eyewitness said the victim was a man who appeared to be in his 50s and was not wearing a shirt as he walked out of the Home Office with police.

A police officer in the doorway of the Home Office building in Westminster this afternoon

A police cordon outside the Home Office in London after the stabbing incident this afternoon

Police officers outside the Government building on Marsham Street in Westminster today

'He had just trousers, nothing on top... He was full of blood. He was escorted by police and paramedics... I saw just the police when the police came. He was coming out from the building - the officers come in and take him out.'

Ms Patel tweeted today: 'All my thoughts are with the victim and their family following horrific unprovoked knife attack on Marsham Street.'

A Metropolitan Police spokesman said: 'Injuries to a man in Marsham Street SW1 have been confirmed as neither life threatening nor life changing.

'Police were called at 1.06pm on Thursday, August 15 to Marsham Street, outside the Home Office, to a report of a man with a knife at the location.

'The Met's specialist firearms officers attended within six minutes to find a man, aged in his 60s, suffering with knife injuries.

Police officers walk in and out of the Government building in Westminster this afternoon

Police officers arrived on motorcycles and cars at the scene on Marsham Street in Westminster

London Ambulance Service attended the road where they helped the injured person

'London Ambulance Service attended the address and took the victim to a central London hospital. The injured man's family has been notified.

'The incident took place outside the building. Officers quickly detained a 29-year-old man, near to the scene Smith Square who was arrested on suspicion of grievous bodily harm and possession of CS spray.

'He was taken to a central London police station where he remains in custody. nquiries are ongoing to establish the circumstances of the incident. We are keeping an open mind about any possible motive at this early stage.

A London Ambulance Service spokesman said: 'We were called at 1:11pm today to Great Peter Street, SW1, to reports of an incident.

Ambulances and paramedics were seen outside the building in London after 1pm today

Police were called to the building following a report of a man with a knife at the location

A general view of the Home Office after the area was cordoned off by police this afternoon

'We dispatched an incident response officer, a medic in a response car, a motorcycle paramedic and an ambulance crew. We treated a man at the scene and took him to a major trauma centre.'

A Home Office spokesman said: 'The Metropolitan Police is investigating a knife attack which took place outside the Home Office this afternoon. The victim is receiving medical care.

'This is a deeply concerning incident and our thoughts are with him and his family. As this is an ongoing investigation it would be inappropriate to comment further.'

The Home Office headquarters are located a short walk away from landmarks including Westminster Abbey and the Houses of Parliament.

** Were you there? Email mark.duell@mailonline.co.uk or call 020 3615 1838 **