The unarmed constable murdered in the Westminster Bridge terror attack was "a proud and courageous police officer who did his job and never wanted any fuss", his friend has said.
Pc Shaun Cartwright paid tribute to Keith Palmer, who was killed as he stood guard at the Palace of Westminster on March 22 last year.
In a statement released through Scotland Yard he said: "Keith loved being a police officer, he just wanted to help people and do his best.
"Keith was always happy, always the first to help anyone out, first in to work and the last one out.
"He was a proud and courageous police officer who did his job and never wanted any fuss or to be the centre of attention.
"Keith was a true and loyal friend, utterly reliable.
"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 officers are expected to attend a number of private memorial services on Thursday to mark the first anniversary of the atrocity, but the force has not made details public.
Pc Palmer's name will be one of 1,400 inscribed on the new UK Police Memorial being built in Staffordshire, commemorating officers who were killed on duty.
Another 4,000 of those who died on duty will be remembered inside the memorial.
Supporters have been asked to donate £5 towards the scheme, for which £3.1 million has been raised of a total £4 million cost.
It includes an education programme to teach children about policing and support scheme for bereaved families.
Sir Hugh Orde, chair of trustees of the UK Police Memorial, said: "This has been an unprecedented year for policing with officers and staff repeatedly putting themselves in danger to keep the public safe and protecting them from harm.
"Sadly, in March last year we saw one of my policing colleagues Pc Keith Palmer lose his life during a terrorist attack in London whilst protecting our freedoms and safeguarding our democracy.
"Keith's death put greater emphasis on the need to create a memorial where the nation can go to commemorate our police service."