One year after the Westminster attack, memorials will take place to remember the victims and survivors of the four terrorist attacks which took place across London last year.
Fourteen people were killed and more than 100 others injured in attacks in Westminster, London Bridge and Borough Market, Finsbury Park mosque and Parsons Green tube station.
Five people were killed and more than 50 injured when Kent-born Khalid Masood drove a car into pedestrians on the south side of Westminster Bridge, before fatally stabbing PC Palmer in New Palace Yard.
MP and trained medic Tobias Ellwood treated PC Cartwright on the scene, but his life couldn’t be saved.
Masood was shot dead by armed police at the scene.
One year on, fellow officer PC Shaun Cartwright, who was arriving at work to take over guard from PC Palmer, has paid tribute to his friend.
Describing the moment he was told of the attack, PC Cartwright told Sky News: I didn’t know who it was. I asked a few people, but I don’t know if they didn’t want to tell me or they didn’t know. Finally someone told me, it’s your friend Keith.
I knew by then that he’d gone. I lost a really good friend. Considering the jobs that we’d done before on the Territorial Support Group (TSG) – drugs raids and rapid entries – you can almost imagine it happening there but not at the Houses of Parliament.
Wherever he was he enjoyed work. He always came in with a smile on his face and just wanted to get on and do his best. I’d have liked to have my friend beside me rather than attending his funeral. It’s not the way it should be. He was proud to be a policeman.
A service of commemoration will take place at midday in Westminster Hall, attended by Home Secretary Amber Rudd.
MPs will also observe a minute’s silence, and the message #LondonUnited will be projected onto the four locations where the attacks took place – London Bridge, Finsbury Park Mosque, Parsons Green underground station and the Houses of Parliament.
A digital book of condolence will be open to the public until 19 June, when it will become part of a 3D installation in City Hall.
London Mayor Sadiq 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.
And we will never forget the courage of PC Keith Palmer, who paid the ultimate sacrifice whilst protecting Parliament.