Officers from Thames Valley Police joined colleagues around the country as they honoured PC Keith Palmer.

The heroic officer was murdered by Khalid Masood when the terrorist attacked the Palace of Westminster on March 22.

Metropolitan Police officer PC Palmer was on duty guarding the palace during the attack, in which four civilians were also killed by Masood, who was later shot dead.

Today TVP officers observed a minute's silence at 2pm as PC Palmer's funeral began at Southwark Cathedral in London.

Chief Constable Francis Habgood travelled to the ceremony, which took place on the day former Oxford area commander Cressida Dick took over as the first female commissioner of the Met.

TVP's flag flew at half-mast above police stations in honour of Pc Palmer.

Ch Con Habgood said: “It is deeply important to have joined our colleagues from police forces across the country to remember PC Keith Palmer and the ultimate sacrifice he made while on duty protecting the public.

"His death is a poignant reminder of the lengths to which officers go while in the line of duty to ensure our communities are kept safe.

"Very sadly the recent death of former Thames Valley Police officer PC Gareth Browning is another pertinent reminder of this.

"Our thoughts remain with the families, friends and colleagues of both men.”

Former TVP chief constable Sara Thornton, now head of the National Police Chief's Council, said the scale of the funeral was unprecedented.

She said: "I don't think we will have ever seen a police funeral of this size.

"Officers from all over the country are coming to London to join their Metropolitan Police colleagues to line the route.

"We all want to pay honour to the ultimate sacrifice that Keith made."

More than 5,000 officers from forces across the country gathered in central London to line the route of PC Palmer's final journey.

His coffin spent last night in the Chapel of St Mary Undercroft in the Palace of Westminster before travelling along a 2.6 mile route through the capital.

The Queen gave permission for his body to rest in the chapel, an honour normally reserved for senior figures such as Baroness Thatcher and Tony Benn in recent years.

Ms Thornton said: "The fact Keith has laid in rest in the Palace of Westminster is a sort of acknowledgement on behalf of the whole country of the sacrifice that he made but also the job that officers do day in, day out."

PC Palmer's name has been added to the roll of honour and remembrance at a ceremony at the National Police Memorial on The Mall, in central London, complete with a guard of honour.

Steve Lloyd, of the Police Roll of Honour Trust, said: "We hope that knowing their loved one's name are to be forever remembered will bring some small comfort to the families of the fallen officers."