Financial markets know neither remorse nor respect. Seconds after police confirmed that Jo Cox was dead last week, the pound rose sharply against the dollar.

Currency traders were buying sterling because their instant assessment was that the MP's death made it less likely Britain will vote to leave the European Union this week; market orthodoxy says Brexit would be negative for the pound.

The American term for a dramatic last-minute political event is an October Surprise, a phrase born in 1972 when Richard Nixon, the then US president, announced peace in Vietnam two weeks before polling day. He was re-elected comfortably. These days, most historians say it did not change November's result.

Before Cox's dreadful killing Leave was winning, because more voters believed the referendum was about immigration than the economy. People who believe immigration is the most important issue almost all plan to vote Leave. People who believe the economy matters most almost all plan to vote Remain. Where does something as moving as a young mother's death fit into that scheme?


Some believe a connection can be made to Remain's tactics over immigration. Hence British Prime Minister David Cameron's reference to the referendum as a choice between the Little England vision he ascribes to Nigel Farage of Ukip and the "open, tolerant" society he says would embrace the EU. Cameron won't mind a bit if those words lead some voters to associate the Leave campaign with Cox's alleged killer.

So if a connection is convincingly drawn between the political rhetoric of the Leave campaign and the actions of Cox's killer, the Remain campaign may feel some political benefit. Some Remainers think Thomas Mair's words at his first court appearance ("Death to traitors and freedom for Britain") can only harm a Leave campaign that bases its case in patriotism and sovereignty.

But this is a path fraught with peril for Remainers, too. Politicians already facing public suspicions that they are cynically manipulating facts to their own ends will pay a heavy price if voters believe they are misusing Cox's death in the hope of winning votes.

And afterwards? Even before Friday, allegations of bad faith and dishonesty played a central part in the political debate, with corrosive effects on relationships. Some people will attribute the result to Cox's death and the way it was presented and explained.

The more Cox's awful death is dragged into the debate, the harder it will be for people divided by that referendum to come back together afterwards.

How soon will we know the result?

Voting begins on Thursday night NZT. It is expected that by about 4pm on Friday we should get a clear idea of what the result is likely to be.

How are the votes counted?

Vote counting will begin as soon as the polls close at 10am on Friday at 382 local centres around the UK. Each area will declare their result as soon as the votes have been counted. These local results will then be collated at 12 regional centres. The final vote will be announced at Manchester Town Hall.