A terror suspect drove at police outside Buckingham Palace and yelled 'Allahu akbar' while reaching for a 4ft sword before he was arrested by three unarmed officers.

The 26-year-old from Luton was wrestled to the ground and incapacitated with CS gas by the officers, two of which suffered injuries, at about 8.30pm last night.

Metropolitan Police said the suspect had been arrested under the Terrorism Act and was currently in custody in a central London police station.

The force revealed how the man had deliberately driven at a police van parked near the Mall roundabout in front of the palace, before stopping in front of the vehicle.

As three unarmed PCs exited the van and approached the blue Toyota Prius, the suspect reached for a 4ft sword in the footwell.

Following a struggle, the suspect and two officers were taken to hospital to be treated for minor injuries, while the third officer did not require treatment.

Officers remain vigilant outside Buckingham Palace after a terror incident at the landmark last night at about 8.30pm

The 26-year-old from Luton was wrestled to the ground and incapacitated with CS gas by the officers, two of which suffered injuries, at about 8.30pm last night

Metropolitan Police revealed how the man had deliberately driven at a police van parked near the Mall roundabout in front of the palace, before stopping in front of the vehicle

A large police cordon is put up at the far end of The Mall. Pictured in the distant background is Buckingham Palace

Commander Dean Haydon, the head of the Met's Counter Terrorism Command, said: 'I would like to pay tribute to the bravery and professionalism of these officers who quickly brought this incident under control.

'Their vigilance, courage and the swiftness of their response demonstrates how our officers are protecting the public at this time.

'Officers from the Counter Terrorism Command are now investigating and searches are being carried out in the Luton area today.

'We believe the man was acting alone and we are not looking for other suspects at this stage.

'While we cannot speculate on what the man was intending to do - this will be determined during the course of the investigation - it is only right that we investigate this as a terrorist incident at this time.

'I would urge anybody who witnessed the incident or has any information or images that may assist the investigation to contact the confidential hotline on 0800 789 321.'

Commander Haydon added: 'This is a timely reminder that the threat from terrorism in the UK remains severe.

'The police, together with the security services, are doing everything we can to protect the public and we already have an enhanced policing plan over the Bank Holiday weekend to keep the public safe.'

As three unarmed PCs exited the van and approached the blue Toyota Prius, the suspect reached for a 4ft sword in the footwell.

Police rushed to the scene and set up a cordon just yards from Buckingham Palace in London

Police had previously described the weapon as a knife but have now said it is a '4ft sword'.

A taxi driver at the scene said: 'I asked an officer if he got away, and he said that there was only one attacker and two coppers got whacked on their hands.

'This bloke had driven on the wrong side of the road and when police came out to challenge him, and say that he had gone the wrong way, the bloke got out the car.

'He had a big machete. He was waving it at the policemen who managed to get him on the ground.

'Hopefully no-one has been badly hurt, there were so many police cars it was a bit of a hold up.'

One woman said her partner had seen the blade and initially though it was a sword.

Eyewitnesses revealed how the hero officers wrestled the man to the ground and received hand injuries. Both have been discharged from hospital

Officers rushed to Buckingham Palace after a man armed with a knife was arrested on Friday night

The Metropolitan Police confirmed no other people were caught up or injured during the incident

One witness described seeing the man wrestled from a car by police having apparently driven his vehicle towards them.

Social media users suggested the alleged attacker was carrying a sword - while others said he was holding a machete.

Kiana Williamson said: 'We turned up and there was one police van and one car, there was also a civilian's car that had veered towards the police car.

'They were trying to get the man out of the car, shouting, more police were arriving on to the scene and the man was fighting back.

'I saw one injured policeman with an injury to his arm although it didn't look severe. He was being tended to by another officer.

'The man had been restrained and looked almost unconscious by the side of the road.

'I didn't see the car driving but the car had been left at the side of the road and an eye witness had said that he had driven towards the police car.'

The whole encounter lasted around one minute, she added.

The Metropolitan Police confirmed a man was arrested on suspicion of GBH and assault after the incident outside Buckingham Palace

The Metropolitan Police said it was too early to know whether the incident was terror related.

Witness Nicole Kyle was walking home when she saw armed police swoop on the scene and quickly put up a cordon.

The 25-year-old consultant said: 'I was walking toward the Mall and St James's Park when I saw police rush down toward the palace in great numbers.

'As we got further down the Mall we saw armed police outside a police van, at which point we were able to walk closer to the palace still, where we were eventually stopped by a cordon.

'All we were told was that there's been an incident.

'A few minutes later police came by to have us clear the area and move further away from the palace.

'We then saw that police had expanded the cordon. It looks like the cordon is continuing to expand.'

Photographs posted online showed police cars outside the palace and armed officers later set up a cordon.

Photographs posted online showed police cars outside the palace and armed officers later set up a cordon

A police officer stood guard at a cordon after police arrested a man carrying a knife outside the palace

The Metropolitan Police confirmed no other people were caught up or injured during the incident.

One police officer at the scene refused to speculate on whether the weapon was a knife or a sword.

But he told MailOnline that since the London Bridge atrocity earlier this year his colleagues feared being involved in an attack.

He said: 'You never think you're going to be in the day these things happen.'

Almost two hours after the incident, cordons around the palace were still in place with huge yellow barriers closed across roads.

At the Admiralty Arch - which leads to the Mall - a group of heavily armed Diplomatic Protection Group officers were allowed through the cordon.

It is more than half a mile from the Palace itself but police have closed down the road as a precaution following last night's attack.

Bemused tourists were shepherded out of the cordon with dozens stopping to ask officers what had happened at the scene.

A police officer stood at a cordon after police arrested a man carrying a knife outside on the Mall

Cordons around the palace were still in place late on Friday night, with huge yellow barriers closed across roads

Detective Superintendent Guy Collings said: 'A man in his mid-twenties has been arrested by police after they spotted a weapon inside his car.

'The quick and brave actions of both officers meant that the suspect was detained very quickly.

'No members of the public had any interaction with this individual at the scene. He will now be questioned by detectives in police custody.

'It is too early in this investigation to speculate any further.'

A force spokesman added: 'Officers are on scene at the Mall outside Buckingham Palace. A man has been arrested on suspicion of GBH and assault on police.

'During the course of detaining him, two male police officers suffered minor injuries to their arm.

'The London Ambulance Service were called and they were treated at the scene. They have not been taken to hospital.

'No others persons have been reported injured. Officers remain on scene and enquiries are ongoing.'

The Queen is not in the capital and is currently staying at her Scottish residence, Balmoral.