London attack: Sea of flowers at Westminster as Londoners pay respects to victims of Khalid Masood

This was the poignant scene after a sea of flowers was laid in Westminster to commemorate the victims of Wednesday’s terror attack.

Scores laid floral tributes outside the Houses of Parliament in the wake of the attack which killed four innocent people and injured dozens more.

“Sick and depraved” terrorist Khalid Masood mowed down pedestrians on Westminster Bridge before stabbing police officer Keith Palmer to death outside the Palace of Westminster.

Among those to leave tributes at the scene of the attack was London Mayor Sadiq Khan, who wrote a note saying: "You will always be in our hearts. Londoners will never forget the innocent people who lost their lives."

Another note, from London's Pakistan Community Centre, read: "Keith Palmer, you sacrificed your life to protect us, we shall never forget you. RIP, thank you."

British Transport Police officers from Lambeth added: "For Pc Keith Palmer. HERO. Never forgotten."

At a vigil in Trafalgar Square on Thursday evening, Mr Khan invited both residents and tourists to join a candlelit memorial at the central London landmark in solidarity with the victims.

Mr Khan had encouraged “everyone visiting our city” to join together in memory of those who lost their lives.

He told the crowd “to show the world that we are more committed than ever to the values that we hold dear - that we remain united and open.”

On Thursday morning a book of condolence was laid in Westminster Hall for MPs, staff and members of the public to write messages to honour those who died.