UK Labour Member of Parliament Jo Cox was killed in the street. Picture: AP

“We have now charged a man with murder,” West Yorkshire Police’s Detective Superintendent Nick Wallen said.

“Thomas Mair, 52, of Birstall, will appear at Westminster Magistrates Court today.”

It comes after Cox’s assistant revealed her boss’s last words as she held the mum-of-two in her arms as she took her last breaths. Her assistant Fazila Aswat held her — just moments after being shot and stabbed in a horrifying attack.

Mrs Aswat’s father Ghulam Maniyar told ITV News: “She was with my daughter.

“They’d left Batley office, they were in the marketplace, she was in my daughter’s car sitting in the back seat. The car stopped and Jo decided to come out,” he said. “My daughter didn’t know she’d been shot.”

“She said her [Jo’s] injury was so bad and she was in her arms. There was lots of blood,” he said. “She said “Jo, get up” but she [Jo] said “no, my pain is too much, Fazila”.

Jo Cox, right, and her assistant Fazila Aswat who was there when she died. Picture: ITV NewsSource:Supplied

“I think those were the last words Jo spoke. She could not do anything else. She tried to comfort her. “Then the police came, the air ambulance came, they took her to hospital. She was a witness and her clothes were full of blood,” he said.

The man suspected of shooting Ms Cox to death is thought to have bought Neo-Nazi material and a munitions handbook online, according to receipts produced by an advocacy organisation.

The southern Poverty Law Centre, which is dedicated to “fighting hate and bigotry” has published receipts for purchases made between 1999 and 2003 which include an Improvised Munitions Handbook and another title called Chemistry of Powder and Explosives.

They were bought along with a Nazi manual called Ich Kampfe and six issues of Free Speech from National Vanguard Books, an arm of the National Alliance which is a US based right-wing group.

The southern Poverty Law Centre describes it as the “most dangerous and best organised Neo-Nazi formation in America”

“NA materials call for the eradication of the Jews and other races and the creation of an all white homeland” it said.

Picture: southern Poverty Law Centre.Source:Supplied

The munitions handbook included instructions on how to assemble a homemade gun. Picture: southern Poverty Law Centre.Source:Supplied

The receipts show the books were sent to Thomas Mair at an address in West Yorkshire in the English area of Batley — the same constituency Mrs Cox represented as an MP.

A copy of a page from inside the Munitions Handbook shows directions for a pipe pistol that can be made from “steel gas or water pipe and fittings” including instructions on how to assemble it and the fact it has a range of 30 metres.

Eyewitness accounts from the scene vary, however one witness said he thought the gun appeared to be old-fashioned or rudimentary in nature and was “about the size of a cucumber”.

Some report hearing a man yell “Britain First” or “put Britain First”.

National Vanguard Books is linked to the National Alliance and promotes the idea that race is based on physical characteristics.

News of Mrs Cox’s death has shocked the UK with hundreds turning out to mourn her from Prime Minister David Cameron to Labour leader Jeremy Corbyn.

Mrs Cox was considered a rising star in politics having only recently entered parliament following a career as an aid worker. She had been vocal in her support for Syrian refugees and supported remaining in the European Union in the divisive debate ahead of next week’s vote.

West Yorkshire police said they are interviewing several eyewitnesses in relation to the shooting and are not looking for any further suspects.

A 77-year-old man was also wounded but his injuries are non-life threatening, police said.

Thomas Mair was said to be a loner suffering from mental illness.Source:Supplied

Labour MP Jo Cox was 41. Picture: AFP.Source:AFP

Labour Party member leaders lay tributes in London. Picture: Dan Kitwood/Getty ImagesSource:Getty Images