On 22 March 2017, Palmer was in New Palace Yard guarding the Palace of Westminster. At approximately 14:40, he was approached by Khalid Masood, who was armed with two knives. Though unarmed, Palmer confronted Masood in an attempt to stop him. Masood fatally injured Palmer during this encounter. By confronting Masood, Palmer delayed him long enough for an armed police officer to arrive and shoot Masood dead.
Funeral
Palmer was granted the rare honour of lying in rest in the Chapel of St Mary Undercroft, Palace of Westminster; other recipients of this honour include: the former Prime Minister Margaret Thatcher in 2013 and the former Postmaster GeneralTony Benn in 2014. On 9 April 2017, his coffin was received into the chapel with a guard of honour of police officers. A private service was then held for his family. Officers kept vigil next to the coffin overnight. The following day, on 10 April, Palmer's coffin travelled in procession to Southwark Cathedral, escorted by motorcycle outriders from the Special Escort Group of the Metropolitan Police. The route was long and avoided Westminster Bridge where the terrorist attack had begun. Instead, the procession crossed the Thames over Lambeth Bridge, during which a ten-second horn salute was given by boats on the river. Tens of thousands of people lined the streets, including 5,000 police officers. The procession was fronted by a colour party carrying the Metropolitan Police Service Standard, who were followed by five mounted police officers. Then came the funeral conductor and chaplains who were walking in front of the hearse. The hearse carried Palmer's coffin which was draped in the police flag, and there were "red and white floral tributes atop the hearse"; these "spelled out 'No 1 Daddy', 'husband', 'son', 'brother', 'uncle' and 'Keith'". Making up the rear were cars carrying his family, and four more mounted officers. Palmer was given a full police funeral at Southwark Cathedral. It was attended by his family and friends, and a number of dignitaries including Cressida Dick, the newly appointed Commissioner of the Metropolitan Police. Dick read the poem Funeral Blues by W. H. Auden at the service which was her first public engagement since taking up the post. The address was given by Andrew Nunn, the Dean of Southwark.
BLM counter protest
In June 2020 during Anti Black Lives Matter protests by veterans angered by vandalism done towards the statue of Sir Winston Churchill, one of the protestors was seen urinating next to PC Palmer’s memorial. He was later jailed for two weeks. Bournemouth MP Tobias Ellwood, who aided Palmer as he lay dying tweeted the following about the image of the man urinating:
"Absolute shame on this man. Of all the images to emerge over these few testing days I find this one of most abhorrent. Please help identify him."
Personal life
Palmer was married to his wife, Michelle. They have a daughter, who was aged five at the time of Palmer's death. Palmer was a supporter of Charlton Athletic F.C. and held a season ticket. The club honoured him by replacing his regular seat at The Valley stadium with "a white chair bearing his warrant number 'P204752'".
Honours
In the 2017 Birthday Honours, Palmer was awarded the George Medal "for confronting an armed terrorist to protect others and Parliament". In recognition of his sacrifice, the Metropolitan Police Service retired his shoulder number and stated that it would "not be reissued to any other officer". His name has been added to the United Kingdom's Police Roll of Honour by the Police Roll of Honour Trust. He was awarded the outstanding bravery of the year award at the 2018 Met Excellence Awards.