Incredible moment New Zealand police perform a haka to honour murdered Sgt Matt Ratana who once protected Princess Diana before being shot by a handcuffed suspect inside a cop shop

A group of New Zealand police officers has performed a haka in honour of their slain colleague who had moved to London to join the Met police force. 

Incredible footage shows police carrying out the traditional Māori dance at Porirua College near Wellington following the shooting of Sergeant Matt Ratana in September in Croydon, South London. 

He was remembered in a service that also paid tribute to New Zealand Constable Matthew Hunt, 28, who was killed in a traffic stop in Massey, West Auckland, in June. 

Sergeant Matiu Ratana (pictured with his partner Sue) was allegedly shot by a 23-year-old man who was detained for possession of ammunition at Croydon custody centre in South London

Speaking during the service on Tuesday, New Zealand Police Commissioner Andrew Coster said: 'Our recruits will perform a haka to the memorial wall. 

'This haka ensures the manner of our slain officers never diminishes. Every new constable at the beginning of their career in police takes part in the haka to the wall as Matthew did.

'The haka says ''let our hearts beat as one, let our thoughts be united, let our cause be collective''. In my view this very eloquently express why we're gathered here today.

'We also take this opportunity to remember London Metropolitan Police Sergeant Matui Ratana who was shot on duty.

'Matui was also a part of the New Zealand police family having served with us from 2003 to 2008. Described by former colleagues as a 'larger than life character', we remember him today.' 

The performance was praised on social media today, with West Midlands Police Chief Superintedent Chris Todd tweeting: 'What an impressive tribute. No need to say anymore...the clip says it all. #RIPMattRatana.'  

Every new constable at the beginning of their career in the New Zealand police takes part in the haka to the memorial wall at Porirua College (pictured today)

Sgt Ratana receiving a long and good service medal from the Commissioner Cressida Dick on May 31 2017. Paying tribute to Sgt Ratana, Dame Cressida told the Evening Standard : 'Matt was a great police officer. He was a fine skipper — our word for a sergeant — and a lovely man, with a ready smile and a big heart.

Originally from Hawke's Bay, Sgt Ratana went to the UK in 1989 while in his early 20s and joined the Metropolitan Police in London two years later.

The popular sergeant then returned to New Zealand to serve for Auckland City and Counties Manukau police between 2003 and 2008, before going back to Britain. 

He also acted as a protection officer for Princess Diana, the Queen Mother and former Prime Minister John Major at one stage.

The 54-year-old was shot as he was preparing to search a handcuffed suspect - widely named as Louis De Zoysa, 23 - who had managed to smuggle a revolver into the custody suite in Croydon, south London on September 25.

He was rushed to hospital after the shooting at  2.15am last Friday - but was tragically pronounced dead after fighting for his life for two hours.

At 11am, colleagues from across the country paid tribute to Sgt Ratana, calling him a close friend who was part of the 'police family'.

Officers up and down Britain observed a minutes silence in memory of Sgt Ratana with many forces sharing images of their solemn tributes to social media. 

A year from retirement, the inspirational police officer had thrown himself into coaching and was looking forward to being able to focus fully on nurturing future rugby stars

The Metropolitan Police Federation account added: 'Colleagues in New Zealand have performed a Haka to remember their fallen colleagues at their Police Remembrance Day service.

'This year they included Sgt Matt Ratana, of the Metropolitan Police, amongst those they remembered. Thank you.'

Sgt Ratana's partner Su Bushby previoulsy paid tribute to her 'gentle giant'.

Speaking for the first time since his death, Ms Bushby, his girlfriend of five years, said he had an 'infectious smile and big heart'. 

De Zoysa, of Norbury, South London, remains in a critical condition in hospital with a neck injury after allegedly shooting himself when five shots were discharged while his hands were handcuffed behind his back. 

The group of New Zealand police officers carried out the traditional Māori dance at Porirua College near Wellington today following a memorial service