British MP killed in shock attack before EU vote

A British lawmaker was killed in a shock daylight street attack on Thursday, throwing campaigning for the referendum on Britain's EU membership into disarray just a week before the crucial vote.

Jo Cox, a 41-year-old mother-of-two from the opposition Labour Party, was left bleeding on the pavement after reportedly being shot and stabbed in the village of Birstall in northern England, according to witnesses quoted by local media.

Police later announced the death of Cox, a campaigner for Britain to remain in the European Union.

Officers said a 52-year-old man had been arrested and a firearm had been recovered from the scene.

"This was a localised incident, albeit one which has a wider impact," West Yorkshire Police and Crime Commissioner Mark Burns-Williamson told reporters.

Cox, a former aid worker, was only elected to parliament last year but had already made her name campaigning for the government to do more to aid Syrian refugees and for Britain to stay in the EU.

After the attack, the "Remain" camp said it was suspending all campaigning for Thursday and Friday while a spokesman for the rival "Vote Leave" group said their "battle bus" was returning to headquarters.

A police forensic officer picks up a bag from the crime scene on the pavement outside the library in Birstall, northern England, where Labour MP Jo Cox was shot. (AFP)

Prime Minister David Cameron cancelled a planned rally during a historic but controversial visit to Gibraltar as part of his campaign for Britain to remain in the EU in the June 23 vote.

"We've lost a great star. She was a great, campaigning MP with huge compassion, with a big heart," Cameron said in televised remarks.

On a visit to Copenhagen, US Secretary of State John Kerry said: "It is an assault on everybody who cares about and has faith in democracy," he added.

Her husband Brendan wrote: "Jo believed in a better world and she fought for it every day of her life."

Over parliament the British flag flew at half-mast.

The human rights campaign group Avaaz called for a vigil outside the Houses of Parliament and a church in Birstall also said it was planning a commemoration later on Thursday.

A video grab shows Jo Cox speaking during a session in the House of Commons in central London on March 21, 2016. (AFP/UK parliamentary recording unit)

Three shots

Grieving local residents laid flowers to near the scene of the attack as police forensic officers were seen examining a shoe and a handbag in a cordoned-off area.

One witness, local cafe owner Clarke Rothwell, said that Cox had been shot three times.

"He shot this lady once and then he shot her again, he fell to the floor, leant over shot her once more in the face area," he told the BBC.

Sky News television quoted unconfirmed reports that the shooter shouted "Britain first".

He was named by British media as local man Tommy Mair.

The attack halted a frantic day of campaigning, as two new opinion polls indicated that more Britons now want to leave the EU than want to stay.

If they prove correct, Britain would become the first state in the nearly six-decade history of the bloc to leave.

People arrive to place floral tributes and candles to slain Labour MP Jo Cox at a vigil in Parliament square in London. (AFP)

Members of the public sign a white board of condolences at the vigil. (AFP)

'Difficult to be optimistic'

The looming prospect of a Brexit has sparked volatility in the financial markets and sent the pound plunging, and prompted interventions from a number of EU leaders.

"I know it's very difficult for us to be optimistic today, we know the latest polls," EU President Donald Tusk said on a visit to Helsinki.

But he added: "The EU will survive, I have no doubt -- it is still much easier to survive when you are 27 member states than completely alone".

At an economic forum in Russia, European Commission chief Jean-Claude Juncker also said: "I don't think that the European Union will be in danger of death if Britain leaves because we continue the process of closer cooperation in Europe."

German Chancellor Angela Merkel used a press conference in Berlin to urge Britain to stay.

She said that in the event of a Brexit, "everything related to the common market, and to the mutual benefit to Britain and all other European member states, would no longer be available to Britain".

A Union flag flies at half mast from the Houses of Parliament in honour of the slain Labour MP. (AFP)

Too close to call

A new survey by Ipsos Mori showed support for leaving the EU now stands at 53 percent compared to 47 percent for those who want to stay in, excluding undecided voters.

Another new poll by Survation put "Leave" ahead by 52-48, excluding undecided voters.

Polling expert John Curtice said the race was now too close to call, telling the BBC: "I think we no longer have a favourite in this referendum."

London's FTSE 100 share index fell 1.1 percent to 5,899, before recovering somewhat to end the day 0.27 percent lower at 5,950.

The pound hit a new two-month low against the euro.

Leading business newspaper the Financial Times endorsed the "Remain" camp, saying Britain had benefited from its 43-year membership of the European fold and leaving would "seriously damage" the economy.

"A vote to withdraw would be irrevocable, a grievous blow to the post-1945 liberal world order," it added.