The 48-year-old father and husband was stabbed to death by Khalid Masood as he carried out his duties on the cobbled forecourt of the Palace of Westminster.
Pc Palmer’s funeral cortege, including his hearse topped with a floral tribute reading No 1 Daddy, left the palace, where his coffin laid in rest overnight, through the Carriage Gates he died defending.
His coffin travelled slowly and amid silence along 2.6 miles of the capital’s usually bustling streets, avoiding the scene of last month’s atrocity on Westminster Bridge on its journey to Southwark Cathedral, in central London.
Around 50 members of Pc Palmer’s family including his wife, child, mother and father, brother and sisters attended the cathedral service, led by the Dean of Southwark the Very Reverend Andrew Nunn and followed by a private cremation.
Home Secretary Amber Rudd, Mayor of London Sadiq Khan and the manager and captain of Pc Palmer’s beloved Charlton Athletic football club, Karl Robinson and Johnnie Jackson, were present.
Met Commissioner Cressida Dick, the first female head of Scotland Yard in its 188-year history, also attended the full force funeral in her first public engagement in her new role.
She read the WH Auden poem Funeral Blues, which begins “Stop all the clocks, cut off the telephone”, and asks for “the traffic police men to wear black cotton gloves” in mourning of a loved one.
Ms Dick told Sky News: “It was a chosen by the family - it was a poem they wanted to have read and for me it was an enormous privilege to be asked to read it. It’s a very powerful poem.”
The Met said more than 5,000 officers from the force and across the country were expected to gather in central London for the service and to line the route, which saw dozens of roads closed to traffic for hours.
Thousands more officers and staff at police stations across the country marked two minutes’ silence at 2pm.
Ms Dick praised the turnout from police and members of the public, who had lined the barriers along the route even hours before the funeral began.
“I think the events at Westminster have appalled the whole nation, that’s quite clear,” Ms Dick said.
“Since then I know, Met colleagues and colleagues from all around the country have been literally overwhelmed by the strength of feeling from members of the public.”
Columns of officers in dress uniform, many with service medals pinned to their jackets and wearing white gloves, lined up near the cathedral as on-duty colleagues involved in the large security operation stood guard.
A burst of sunshine broke through the clouds as Pc Palmer’s funeral procession wound its course up the packed Borough High Street.
A hushed silence interrupted the swell of by-standers lining the procession’s route as it passed, while tourists and locals leant over barricades on one of London’s busiest arteries between the City of London and Southwark.
The hearse passed to the sound of organ music from the nearby cathedral, broadcast to the street over a PA system hanging from a lamppost.
Some members of the public and police shed tears as the procession went past, while members of Pc Palmer’s family and friends followed the hearse in solemn black cars at the rear.
The procession was led by the Metropolitan Police Colour Party and a Black Escort of mounted officers before the coffin was carried into the cathedral by colleagues and friends of Pc Palmer.
Two National Police Air Service helicopters also performed a flypast and aerial salute.
Screens and PA systems were erected for members of the public outside to watch and listen to the service, while inside the Met’s senior chaplain, the Reverend Prebendary Jonathan Osborne, led prayers and Chief Inspector Neil Sawyer, who worked with Pc Palmer in Bromley and the Territorial Support Group, paid tribute.
Hymns including I Heard The Voice Of Jesus Say were followed by a rendition of The Last Post by a bugler from the Honourable Artillery Company.
Officers bowed their heads as the Last Post sounded from the cathedral shortly after a recital of The Lord’s Prayer.
The crowds swelled as passers-by stopped to join those already listening to the service from the PA systems surrounding the cathedral.
A few moments’ silence then followed a rendition of God Save The Queen, as on-duty officers, medical staff and members of the public stood still in respect for Pc Palmer.
At the end of the service, his coffin was again placed inside the hearse, which also had floral tributes reading “husband”, “uncle”, “Keith” and “son”, and driven away to a private ceremony for family and friends.