CUMBRIA'S MPs last night told how London came under attack as they went about their daily work.

Four people died and at least 20 others were injured after a terrorist struck in the heart of Westminster.

A police officer who was stabbed at the Houses of Parliament and his attacker were among the dead, according to Metropolitan Police Acting Deputy Commissioner and head of counter terrorism Mark Rowley.

Barrow and Furness MP John Woodcock said: “I was on my way to vote with a crowd of MPs through Old Palace Yard, in sight of Parliament Square, when shots were fired and we were all ushered at top speed back to a secluded part of Portcullis House.

"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 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."

The attacker, armed with two large knives, mowed down pedestrians with his car on Westminster Bridge, including schoolchildren, then rushed at the gates in front of the Houses of Parliament, stabbing the policeman before being shot dead by other officers.

Eyewitnesses described scenes of terror when gunfire rang out as the man approached a second officer.

Scotland Yard's top anti-terror officer Mr Rowley, standing outside New Scotland Yard, just yards from the scene of the attack, said: "This was a day we've planned for but hoped would never happen. Sadly it is now a reality."

Paramedics fought to save the officer's life and that of his attacker on the floor of the cobbled courtyard in front of parliament, with Foreign Office minister Tobias Ellwood among those who rushed to help.

The police officer was wheeled away on a stretcher with his face covered.

Mr Ellwood, who lost his brother in the Bali bombing, could be seen pumping the officer's chest then standing above him, his hands and face smeared with blood.

Other armed officers, some in plain clothes and wearing balaclavas, swarmed around the yard just feet from where MPs had earlier attended Prime Minister's Questions.

The knifeman drove a grey Hyundai i40 across Westminster Bridge before crashing it into railings then running through the gates of the Palace of Westminster.

His attack left a trail of destruction as paramedics tended to victims on the bridge and at the gate.

One woman hit by the attacker's car before he reached parliament was confirmed dead by a doctor at St Thomas' Hospital. She said others on the bridge suffered 'catastrophic injuries'.

Another woman who apparently fell into the Thames was rescued and given urgent medical treatment on a nearby pier.

London Ambulance Service said paramedics had treated at least 10 patients on Westminster Bridge.

A party of French schoolchildren were among those targeted on the bridge, with three injured.

Downing Street said Prime Minister Theresa May, who was ushered away from Parliament after the attack, was chairing a meeting of the government's emergency Cobra committee.

Mrs May was seen being ushered into a silver Jaguar car in the grounds of the palace as what sounded like gunfire rang out at around 2.45pm.

Meanwhile, hundreds of MPs were placed in lockdown at a number of locations.

Westmorland and Lonsdale MP and leader of the Liberal Democrats Tim Farrow told how the attack happened 50 yards from his base.

He said: "I was on my way to a meeting with Jackie Daniel from the hospital trust (chief executive of the University Hospitals of Morecambe Bay NHS Foundation Trust).

"I was with a group of between 200 and 300 people, we were all bundled out through a small revolving door by police and taken to New Scotland Yard. It was terrifying."

An air ambulance landed in Parliament Square and a regular ambulance came in through the front gates as medics rushed to help.

Armed police cleared the area around the incident and Parliament Square and surrounding streets were closed to traffic while parliament went into lockdown.

As the sitting in the House of Commons was suspended, Commons leader David Lidington told MPs: "What I am able to say to the house is there has been a serious incident within the estate.

"It seems that a police officer has been stabbed, and that the alleged assailant was shot by armed police."

Witnesses described seeing a heavy-set man carrying a knife and running towards the Houses of Parliament.

Jayne Wilkinson said: "We were taking photos of Big Ben and we saw all the people running towards us, and then there was an Asian guy in about his 40s carrying a knife about seven or eight inches long.

"And then there were three shots fired, and then we crossed the road and looked over. The man was on the floor with blood."

Jackie Daniel, chief executive of the trust in charge of Furness General Hospital, was in Westminster ahead of a meeting with MP Tim Farron at the time of the attack.

She was among those evacuated to a secure room in parliament along with University Hospitals of Morecambe Bay Trust chairman Pearse Butler and its director of communications Phil Woodford.

Mrs Daniel, who described scenes in the aftermath of the incident as 'chaotic', said: “Myself, Pearse, and our colleagues are safe, and we would like to send our thoughts and condolences to those tragically affected by today’s events.”