Plans have been revealed for a memorial for victims and survivors of the four terror attacks in London last year.

Well-wishers will be able to leave messages in a digital book of hope at City Hall from Thursday, a year since Khalid Masood ploughed into pedestrians on Westminster Bridge before fatally stabbing unarmed police officer Keith Palmer.

Members of the public will be able to send messages to the installation – which will remain open until June – using #LondonUnited on social media, and their words will be projected on to a map of the capital.

Incident at London Bridge
London Mayor Sadiq Khan (Yui Mok/PA)

The tribute has been set up to mark the four terrorist atrocities that took place in the city last year – at Westminster Bridge, London Bridge, Finsbury Park and Parsons Green.

The phrase #LondonUnited will be projected on to the Houses of Parliament, London Bridge, Finsbury Park Mosque and Parsons Green Tube station on the anniversaries of the attacks.

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.

“These were not only attacks on our city and our country, but on the very heart of our democracy and the values we cherish most – freedom, justice and tolerance.

“We know that families, friends and communities have their own private arrangements in place to mark this tragic anniversary, and our plans here at City Hall are intended to complement, without intruding on, individual private commemorations.

“I hope these arrangements will help people to come together and remember those who were killed and injured, to show solidarity and support for their families and friends and the people whose lives have been affected by these tragic attacks.

“As we enter this period of remembrance and reflection, we stand together as Londoners, united against terrorism and in hope for the future.”

Terror attacks in UK
Pc Keith Palmer was fatally stabbed in the attack outside the Houses of Parliament (John Stilwell/PA)

Five innocent people were killed in Masood’s rampage – 48-year-old Pc Palmer, who was on duty at the Palace of Westminster, along with US tourist Kurt Cochran, Romanian tourist Andreea Cristea, 31, and Britons Aysha Frade, 44, and 75-year-old Leslie Rhodes, who were mown down on the bridge.

The planned memorial was agreed following meetings with bereaved families, survivors, members of the emergency services and local councils.

Leader of Westminster City Council Nickie Aiken said she would join the Lord Mayor to lay flowers in Parliament Square on Thursday.

She said: “This week’s anniversary will inevitably lead to feelings of huge sadness and loss for so many.

“But we will continue to stand together, united by what we have in common and not what separates us.

“That will be the true legacy of a senseless act of violence and murderous hate.

“It will only make the bonds that bind us all together even stronger.”