THREE North Yorkshire MPs have been locked inside the Houses of Parliament after a terror attack in London.

Five people have died and 40 others injured after a car drove along Westminster Bridge and an assailant attempted to launch an attack on Parliament.

One of those dead is a policeman after he was stabbed by an attacker in a major security incident at the Houses of Parliament.

According to the Press Association, around three shots rang out outside the Palace of Westminster after a man ran through the gates into the front yard of the parliamentary compound apparently waving a knife.

Two people were seen being treated on the ground in New Palace Yard amid shouts and screams.

Rachael Maskell, MP for York Central, Julian Sturdy, MP for York Outer, and Malton MP Kevin Hollinrake have been told to stay inside the Westminster building for their own safety.

Mr Sturdy said he walked past where the police officer was attacked about a minute before the incident. 

Security forces have subsequently swept the building, he said. Mr Sturdy, along with many other MPs, Lords and a group of school children have been evacuated to the Speaker's Courtyard.

He said: "What has happened on Westminster Bridge sounds horrific. My thoughts and prayers are with all of the victims of what is unfolding to be a terrorist act."  

Ms Maskell said: "I had just crossed over from a meeting to vote, so the incident took place after this and I was not aware until I had voted.

"There clearly have been casualties and my thoughts are with their families and with our security staff and police."

Mr Hollinrake is currently with other MPs and staff in an undisclosed but secure part of the building.

He said that after the shooting the area was quickly made secure and the area has been in lockdown since, adding that much of their information has been coming from media outside the building.

“It’s fairly calm in here now,” he said. “We’ve got security forces in here, and we’ve all been taken into a secure room as a precautionary measure.”

He added he had been in a meeting in the office of the leader of the house, just off the Chamber, when they heard shots outside.

“We looked out the window, there were lots of people running.”

Staff for Julian Sturdy said he had text to say he was safe.  It is not clear where he is in the building, however, all of his staff in Westminster have been told to remain in their offices.

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

Armed police cleared the area around the incident and Parliament Square was closed to traffic.

A Downing Street source confirmed that Prime Minister Theresa May was "OK".

Mrs May was seen being ushered into a silver Jaguar car as what sounded like gunfire rang out at Parliament during the incident at around 2.45pm.

Commenting on the day’s events, the Chief Constable of North Yorkshire Police said: "By now many people will have seen news coverage of the attack that took place at Westminster earlier today. 

"I would like to reassure the public that there is no intelligence to suggest that there has been any change in the level of risk here in North Yorkshire.  Nevertheless, in line with other police forces, we will continue to keep our contingency planning under close review, and make careful assessments of the security around any special events.

"On behalf of North Yorkshire Police I would like express my deepest sympathy to those who have lost loved ones, or who have suffered as a result of this attack. 

"Our thoughts are with those people, and with our colleagues in the Metropolitan Police and other emergency services at this difficult time.”