Any day now the High Court will rule on a case brought by two expats, Second World War veteran Harry Shindler, 94, who lives in Italy, and Jacquelyn MacLennan, a lawyer living in Belgium.

They are seeking to overturn the 15-year rule on two principal grounds: first, it is disproportionate because it prevents from voting the very people likely to be most affected by the outcome of the referendum; and second, it penalises people for exercising their free movement rights in breach of EU law. Indeed, lawyers for the claimants don’t call them expatriates but “Britons in Europe”.

The Government insists it is operating the same voting rules applied in a general election but this is not the case. Indeed, there are some perplexing anomalies.

For instance, Irish or Commonwealth citizens living in Gibraltar for any length of time can vote in the referendum, whereas a UK citizen resident in Gibraltar who has been out of the country for 15 years can’t. What is the rationale behind that?