Glasgow, United Kingdom - The British electorate have not lacked direct political engagement in recent years. From the September 18, 2014 Scottish independence referendum to last year's UK general election and even last month's national parliament and assembly elections across Scotland, Wales and Northern Ireland, the popular will of Britain's voting public has loomed large.

Tomorrow, on June 23, voters across all four corners of the United Kingdom will wearily trudge to the polling booths to exercise their democratic right in yet another crucial political decision - whether their country should remain in or leave the European Union of which it has been a member for decades.

Seen by both sides of the debate as Britain's most important decision in recent political history, the EU referendum campaign came to a (temporary) tragic halt when British Labour Party MP Jo Cox was murdered in her English constituency in West Yorkshire last week. For many observers, Cox's death, allegedly at the hands of suspect Thomas Mair who is believed to have had far-right sympathies, was the terrible nadir to a political campaign that had turned sour long ago.

"The general tone of political debate [in Britain] has reached the point where politicians are almost despised by the population," said British political blogger Mark Thompson to Al Jazeera.

He said that this has not just been apparent during the referendum campaign itself, but had been symptomatic of British political discourse for years. "And, so therefore, you could certainly imagine a situation where someone who had psychological issues and who had become radicalised on the right-wing could get it into their head that actually politicians are worthless."

Indeed, prior to the death of pro-EU Cox, a 41-year-old wife and mother-of-two who only won her West Yorkshire seat in last year's UK general election, both sides of the EU referendum campaign had been accused of malicious scaremongering.

Last month, British Prime Minister David Cameron on the Remain side claimed that Islamic terror group the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) would welcome a British exit from the EU.

And just last week, Leave's Nigel Farage, the leader of the anti-EU UK Independence Party (UKIP), unveiled a controversial "anti-migrant" poster - just hours before Cox's death - that drew comparisons with fascist propaganda from 1930s Germany.

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Voting to stay

For millions of people across the UK, accusations that the EU referendum campaign has generated more heat than light have not only come from British citizens, but also the country's large immigrant population of which only Irish citizens and those from the Commonwealth have a right to vote in the in/out EU plebiscite.

"I feel the whole atmosphere has been charged with a lot of emotional overtones around this issue of Brexit," said 38-year-old Nino Puglisi, an Italian national who works as a scientist in the English city of Oxford, to Al Jazeera. "There are racist overtones too - which is the sad truth as well."

Puglisi, who lives in London and who hopes that the UK votes to retain its EU status, added: "Immigrants in this country have contributed significantly to the economy - the overwhelming majority are financially active and are making a fantastic contribution to British society."

Australian Tahnee Conn, who works as an occupational therapist in Glasgow, Scotland, has also been left frustrated by the EU campaign.

She told Al Jazeera that while the Remain side had struggled to articulate the positive case for Britain staying within the EU, the Leave side had appeared "border-line racist". And like Thompson, she also speculated that Cox's death was a tragic result of Britain's highly-charged political atmosphere.

"When there's all this negativity and hostility in the media, people take hold of it - and probably people with mental illness or who have an extreme agenda get wound up by that negativity pervasive in the media," said the 38-year-old who will be voting to remain in the EU.

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Leave supporters

With the result too close to call, Britain's Leave supporters, many of whom have been persuaded that a vote to withdraw from the EU is a vote to regain control over their country's borders, reject the notion that their side's focus on immigration has been racist.

One Leave voter told Al Jazeera that it wasn't immigration itself that concerned him, but the UK's ability to control it.

"There's a housing shortage, the school's are overcrowded and the [British National Health Service] is struggling - you just can't accept the quantity of people coming into the country like this forever," said Stephen Reader, a retired engineer from Derby in the English Midlands.

Yet, it is the death of Cox, which has dominated many thoughts in the run up to tomorrow's vote.

Speculation as to the political significance of Cox's assassination has been rife in the British press with most focusing on the alleged killer's apparent fixation with the far-right. Indeed, during his court appearance after his arrest, Mair gave his name as "death to traitors, freedom for Britain".

Political blogger Thompson contended that with the rise of radical right-wing party UKIP - which won the European Parliament elections in Britain in 2014 and secured nearly four million votes in last year's UK general election - has come a ramping up of the political rhetoric surrounding immigration into the UK - which has itself fed into the referendum campaign.

"Although not all UKIP politicians are guilty of this, quite a lot of them are guilty of exhibiting the kind of views that were not really accepted within the political mainstream a few years ago," said Thompson.

He added that elements like the Farage-issued poster, which portrayed a queue of migrants under the slogan "Breaking Point", were "giving legitimacy to people who have even more extreme views" - although the UKIP leader angrily hit out at any suggestion that Cox's alleged killer had in someway been motivated by the Leave campaign.

In the wake of Cox's murder, there have been calls to reduce the toxicity of UK politics, with an appeal to the British public to show greater respect to their country's elected representatives, most of whom work tirelessly for the constituents they have been elected to serve.

Yet, irrespective of the referendum result, Thompson believes that any ambitions to inject a calmer and more reasoned air into the domestic political scene may be difficult to come by.

"I would hope that after what happened with Jo Cox everyone would pause and reflect and things would maybe be better - but I fear that that won't happen," he stated.

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Follow Alasdair Soussi on Twitter: @AlasdairSoussi