Everything from who gets to use what lanes at the airport to tax havens and energy markets is up for debate ahead of a referendum on UK membership of the EU. Picture: Oli Scarff/Getty Images

That’s when the Belgian businessman, who has married an English woman, had five children and started a company in the UK could find himself a migrant overnight in the country he has called home for 25 years.

But the quietly spoken man is not dwelling on the fact he has no say in an upcoming vote that will drastically affect his life — he simply wants the millions of Brits that do have one to use it.

“I have a huge amount at stake,” he said regarding the June 23 referendum on whether or not the UK will remain part of the European Union.

“[But] if you really take the time of going through the arguments, you turn people around.”

He’s now working with the European Movement urging the estimated two million Brits in Europe and up to 1.2 million in Australia to have their say in a vote poised on a knife edge.

With turnout predicted to be between 40 and 60 per cent, Brits overseas are becoming an increasingly critical part of the campaign. The pro-Europe movement is calling on them to register before May 16 to ensure their vote is recorded.

They also want the UK Electoral Commission to extend this date to allow time for those overseas to register for the choice that could change everything from rules on travel visas to tax havens and how to tackle terrorism. The final deadline for registration is June 7.

At present, Brits who have been living overseas for less than 15 years are eligible to vote, as are Commonwealth citizens in the UK. However European nationals in Britain are not, hence the situation Guy de Selliers finds himself in, where his UK-born children have the right to decide his fate.

European Movement chair Laura Sandys said he’s one of the millions who could find their right to live, work, receive healthcare and education in their adopted home under threat — not to mention the cross cultural marriages that could face questions.

“We are so interconnected as human beings, how do you untangle all of this?” she said.

British Prime Minister David Cameron has triggered a huge split within his party by promising a referendum on the issue, which many say could jeopardise his legacy as PM. Picture: AFP/Leon NealSource:AFP

CRITICAL CHOICE ON JUNE 23

Mr de Seilliers’ situation is just one in a complex and heated debate that has ratcheted up a gear on both sides this week as the countdown begins in earnest.

On one hand, Prime Minister David Cameron leading the ‘In’ campaign, wants Britain to stay part of Europe, saying the EU is a crucial part of making Britain richer and stronger by amplifying their voice in international affairs and providing access to a 500-million member single market for goods and services that benefits the UK economically.

On the other hand, former London mayor Boris Johnson — who is widely tipped to be Mr Cameron’s successor — has split with his party colleague and is leading the ‘out’ camp. He argues NATO is the primary force that has provided security for the UK and wants Brits to choose “freedom” from the European headquarters in Brussels which is blamed for imposing regulatory minutiae and stifling innovation with bureaucratic red-tape.

In between, voters have been bombarded with information from all sides including warnings over jobs, the economy, travel, mobile phone charges and even whether their favourite Premier League footballers would be allowed into the country. A poll shows the vote poised as 50 per cent in favour of leaving to 50 per cent wanting to remain, with bookies odds suggesting a 71 per cent chance Britain will remain in the EU.

Former London mayor Boris Johnson is leading the leave camp in what is being seen as a battle of wills between himself and David Cameron. Picture: Jack Taylor/Getty Images.Source:Getty Images

This week the independent National Institute of Economic and Social Research warned the British pound could slump 20 per cent if Britain votes to leave, triggering turmoil in financial markets and lowering growth forecasts for the UK.

It follows similarly dire warnings from the IMF and OECD, as well as a much publicised intervention from President Barack Obama last month who said the UK would be at the “back of the queue” when it comes to negotiating an independent trade deal with the US.

But despite the economic arguments, polls show voters remain unconvinced by the fact the UK could be better off inside Europe, with fears over immigration and the loss of local control expected to play a large part in the way people vote on June 23.

On Wednesday former Labour Prime Minister Gordon Brown acknowledged globalisation had been seen as a “runaway train” that had created as many opportunities as risks for voters as he kicked off a pro-Europe campaign.

“It’s not just about economy, it’s about culture, economy, how safe we are, how secure we are and what people think our identity is going to be in future,” he said.

“Too much co-operation and people will feel their identity is at risk … the future lies in the united Europe of states, not the United States of Europe.”

Meanwhile leader of the House of Commons Chris Grayling, slammed the former leader as a “disaster” saying the UK was sending millions of pounds a week to Europe.

“Gordon Brown’s EU policies when he was in office were a disaster. He gave away huge amounts of money to the EU when they cut our rebate, he broke his promise to hold a referendum on the Lisbon Treaty and he gave away many new powers to Brussels,” he said.

For more information on the Brexit debate, visit Register2Stay, Stronger In or Vote Leave.

Victoria.craw@news.com.au

US President Barack Obama sparked controversy in the UK last month by saying the UK would be at the ‘back of the queue’ when it comes to negotiating a free trade deal with the US if it votes to leave Europe. Picture: AFP/Justin TallisSource:AFP