FOUR people have been confirmed dead with at least 40 others injured following the terrifying scenes seen in London yesterday.

A single attacker mowed down pedestrians on Westminster Bridge before entering the grounds of the Palace of Westminster where he stabbed 48-year-old officer PC Keith Palmer – a father and husband – to death.

The assailant was then shot and killed by other officers. Two members of the public died during the ordeal and the incident is being treated as a terrorist attack.

The attacker was named on Thursday afternoon as 52-year-old Khalid Masood, who was last known to be living in the West Midlands.

He was said to be known to security services, but only as a 'peripheral' figure.

One of the fatalaties was identified as 43-year-old mum-of-two Aysha Frade. It has been said she was walking across Westminster Bridge to collect her two children from school when she was killed.

The other was revealed to be an American tourist, Kurt W. Cochran.

Parliament was held in lockdown in the aftermath of the incident as the heroic emergency services worked tirelessly to save the lives of those who lay injured, not knowing if they were endangering their own lives.

Following the attack, police conducted raids in London, Birmingham, and other parts of the country, resulting in seven arrests.

Former Chief Constable of Cumbria Police Craig Mackey is being treated as a significant witness. Now the acting commissioner of the Metropolitan Police, Mr Mackey was in the Westminster when the attack happened.

Last night Prime Minister Theresa May spoke defiantly to say the UK would not be intimidated by terrorism.

“Our thoughts and prayers go out to all who have been affected – to the victims themselves, and their family and friends who waved their loved ones off, but will not now be welcoming them home,” she said.

“‘On behalf of the whole country, I want to pay tribute to them – and to all our emergency services – for the work they have been doing to reassure the public and bring security back to the streets of our Capital City.

“‘The location of this attack was no accident. The terrorists chose to strike at the heart of our Capital City, where people of all nationalities, religions and cultures come together to celebrate the values of liberty, democracy and freedom of speech.

“But let me make it clear today, as I have had cause to do before: any attempt to defeat those values through violence and terror is doomed to failure.”

Yesterday, while being held in New Scotland Yard as events unfolded, South Lakes MP Tim Farron spoke to the Gazette to describe the events.

"There was a moment of blind panic with police having to deal with a serious incident. It's pretty scary actually,” he said.

"I heard shots fired, others heard shots. You see a lot of these things on television, it's very sobering when you actually see it.

“I believe the assailant has been dealt with. Police have told me the attacker’s weapon was a knife and he was taken out by police.”

Barrow and Furness MP John Woodcock, who was also at Westminster, said: “Days like this remind us all of the enormous debt we in public life owe to the men and women who put themselves in harm’s way to keep us safe. It is devastating to learn that the police officer who stepped up to protect us from the attack has lost his life and I know that everyone in parliament will want to come together tomorrow to grieve his loss. We will also thank everyone who serves their country by protecting the heart of its democracy.

“Unfortunately there will always be opportunities for individuals or groups to inflict harm in the name of one twisted cause or another. The best response is to protect ourselves as best we can and show, at every opportunity, that Britain will never be cowed by violence and terror.

“So I hope we can all get back to normal as soon as possible and so deny the attacker the publicity on which terrorists thrive.”

Last night it was revealed that PC Palmer, of the Parliamentary and Diplomatic Protection Command, died from the injuries he sustained in the attack. It was reported he had confronted the knife-wielding attacker despite being unarmed himself.

More to come as the details of yesterday's events develop.