With the date of the Brexit referendum approaching - it's set for Thursday the 23rd of June - advisers and tax experts say they're hearing concerns among some expats, in Europe in particular, that the act of voting might threaten their UK non-dom status.
The right to vote in the referendum is open to all UK nationals living abroad who are over the age of 18 and who have been on the electoral register in the UK in the past 15 years, according to the overseas voter pages of the information website, Aboutmyvote.co.uk.
Commonwealth citizens in Gibraltar are also eligible, according to the Government.
(A High Court bid by two expats, living in Italy and Belgium respectively,who were seeking to vote even though they'd lived abroad for more than 15 years, was rejected yesterday. The two had argued that the results of the referendum would directly affect them, and others in a similar situation, and that the 15-year cut-off was "arbitrary".)
But some advisers, like their clients, have wondered whether HM Revenue & Customs might, at some later date, produce documentation of expatriates who voted in the referendum as evidence that they had failed to sufficiently break their ties the UK to be convincing in their claim to have fully left it.
Mark Davies, managing director of London-based Mark Davies & Associates, a specialist tax advice office, said he would generally advise a non-dom client — such as a retired person living in Spain — that voting in an ordinary general election might be seen as showing a "connection" to the UK that could be seen as unusual for someone who was claiming to have "abandoned all" of their connections to it.
"In being able to demonstrate a domicile of choice, the individual has to be able to demonstrate they've abandoned all ties to the UK," he said.
"So if they're evidently engaged in UK political activity, that must introduce some doubt" about the person's true degree of separation.
Nevertheless, he admitted that if the individual didn't have such other common links to the UK that many non-doms have, such as properties in Britain, close family members and a record of frequent and lengthy visits, voting in a referendum on whether Britain ought to remain in the EU - particularly given its potential effects on them in their domicile of choice - probably wouldn't cause a problem.
Gerry Brown, technical manager for Prudential, also believes those non-dom expats wanting to vote in the referendum should have little to worry about, since the Finance Act of 1996 ("Section 200") makes it clear that the authorities are "not to take into account" the fact that someone has voted in a UK election in determining whether they are UK domiciled.
"The test is based on staying in their new country of residence," he told International Investment.
"Voting in a referendum does not involve coming to the UK."
This news, he adds, will possibly be a relief for many British expats currently living in the EU, because many of them may well wish to vote for the UK to remain a member.
This is not only because a departure by Britain might complicate their residency status in their adopted country, he noted, but because they might, for example, "believe it would be good for the Spanish economy, and thus me, to have the UK remain in the EU, if I lived in Spain".
Gibraltar residents in particular are said to view staying in the EU as important for their jurisdiction's continued future, as its chief minister, Fabian Picardo, explained in comments reported in the Daily Mail last month. A "real friend" of Gibraltar wouldn't vote in favour of Brexit, Picardo said.
He added that the consequences of Brexit would be "so potentially dangerous to Gibraltar and the risks to which we will be exposed are so huge that I think if you really put on your thinking cap for Gibraltar, you would only come to the conclusion that Brexit is an unnecessary risk to take".
According to Brown, the relevant passage in the Finance Act reads as follows: "In determining … for the purposes of inheritance tax … where a person is domiciled … there shall be disregarded any relevant action taken by that person … in connection with electoral rights.
"Relevant action is taken by a person in connection with electoral rights where… he does anything with a view to, or in connection with, being registered as an overseas elector; or, when registered as an overseas elector, he votes in any election at which he is entitled to vote by virtue of being so registered."
Finally, as far as HM Revenue & Customs is concerned, there would appear to be no issue: According to its Guidance Note on the matter of residence and domicile, published in September 2015, "The fact that you register and vote as an overseas elector is not normally taken into account when deciding whether or not you are domiciled in the UK". (The relevant section begins on page 24.)
For more information on the referendum, click here. Anyone wishing to vote must register by 7 June.