Media playback is unsupported on your device Media caption "It's the good people that win", says Tory MP Tobias Ellwood

A year on from the Westminster attack, the MP who tried to save the life of a stabbed policeman has recalled the "eerie" silence after the officer died.

Defence minister Tobias Ellwood, who gave mouth-to-mouth to PC Keith Palmer, said he returned home to see his son in tears asking why someone had been killed and why his Dad had helped.

"All I could offer was there are some bad people in the world, but... it's the good people that win," he said.

Five people were killed on 22 March.

Khalid Masood drove his car at people on Westminster Bridge before stabbing PC Palmer in the Palace of Westminster.

Three people were killed outright on the bridge and one died later in hospital, but BBC's Newsnight has learned it could have been worse.

Security sources told the programme that barriers outside Parliament saved 25-30 lives on the day of the attack, as they forced Masood's car off the pavement and onto the road.

At the end of the barriers he cut back into the pavement and crashed in New Palace Yard before attacking PC Palmer.

'Acted alone'

Newsnight's investigation found Masood was trying to move to Saudi Arabia in May 2016, nearly a year before the attack. However, his work visa was turned down.

Meanwhile, police investigating Masood's background suspected him of radicalising another man and giving him religious instructions - but the man was arrested and released without charge.

The police and MI5 concluded that Masood had acted alone.

Mr Ellwood, who is medically trained, said he was one of a number of people that stepped forward that day.

"Eventually the doctor said ok, I think we're going to have to call it. I remember looking at him and saying, 'you're going to have to tell me to stop, sir, because otherwise I'm going to keep doing this'," said the MP, whose brother died in the 2002 Bali bombing terror attack.

"I do recall the silence. It was very eerie. Not a single movement of traffic, not a horn, not anybody speaking, no shouts, nothing whatsoever... I was then left there with a couple of the original policeman, who by this time were very, very upset because it was their colleague."

Image copyright EPA

Events have been held to remember 14 people killed in four London terror attacks in 2017.

MPs observed a minute's silence in the Commons to remember the dead, while Prime Minister Theresa May has laid a floral tribute outside parliament.

Image copyright EPA Image caption Police officers are among those who have paid their respects outside parliament

Culture Secretary Matt Hancock said those who had lost their lives defending democracy "will not be forgotten".

Speaker John Bercow, the Archbishop of Canterbury and the head of the Metropolitan Police, Cressida Dick, were among those to attend a vigil of remembrance at Westminster Hall.

"A year ago today, on this estate and on Westminster bridge, we were visited by what I regard as evil," said Speaker's Chaplain Rev Rose Hudson-Wilkin, who led the service.

Image caption #LondonUnited is being projected in four places where terror attacks took place in the capital last year

The message #LondonUnited will be projected in four locations "as an act of solidarity".

London Bridge, Finsbury Park Mosque, Parsons Green underground station, and the Houses of Parliament will have the phrase projected on them overnight.

The Mayor of London Sadiq Khan said Londoners stood together, "united against terrorism and in hope for the future".

The mayor's office has also organised a digital book of condolence that the public can send messages of solidarity to.

The book will become part of a 3D installation in City Hall that will be open to the public until 19 June - the anniversary of the Finsbury Park attack.

A year of terror in London

Colleagues and family members have paid tribute to the victims of the Westminster attack.

A colleague of PC Keith Palmer, the officer who was stabbed when he confronted Masood at the Palace of Westminster, said the officer was a "loyal friend", "always happy" and dedicated to his job, his daughter and his wife.

Image copyright PA/Facebook Image caption (From left) PC Keith Palmer, Kurt Cochran and Aysha Frade all died in the Westminster attack

PC Shaun Cartwright said: "Keith loved being a police officer, he just wanted to help people and do his best.

"Most of all I will remember him as a family man who idolised his wife, daughter and his family; they're the important ones that I think about a year on from the Westminster attack."

Senior police officers are expected to attend a number of private memorial services later.

Media playback is unsupported on your device Media caption Tobias Ellwood MP told Newsnight: "It was very eerie ... not a horn, no shouts... nothing whatsoever"

The sister of Andrea Cristea, a Romanian tourist who was hurled into the River Thames after Masood's car hit her, has spoken about how she refuses to dwell on her killer.

Speaking to BBC London, Magda Toi said thinking of Masood only made her angry. "My sister is dead and no-one and nothing will bring her back," she said.

Image caption Andreea Cristea had been on holiday with her partner Andrei Burnaz

Ms Toi told of how her family had been given hope when Ms Cristea was recovered from the river alive after surviving the 20ft (6m) fall from Westminster Bridge.

"We desperately hoped that she wouldn't die. She survived the brain operation and we thought - she has a chance. But she didn't."

Ms Cristea died two weeks later and was buried in her hometown of Constanța, Romania.

Mr Khan said: "Londoners will never forget the horrific terror attacks on our city in 2017.

"We will never forget the bravery of our emergency services and first responders who ran towards danger while urging the rest of us to run to safety."