The number of Irish passports issued to Britain is expected to double this year compared with 2015, which was the last year before the Brexit vote, says Ireland’s ambassador to the UK.
Dan Mulhall told BBC Radio 4 that the surge in passport demand could be attributed to the Brexit vote.
He has previously said around 50,000 Irish passports are usually issued in Britain each year, RTE reports.
"I'm responsible, obviously, for our passport operation here in Britain, and for the five years up to last year the demand was pretty flat, and last year it rose by 40%.
"That rise was all in the second half of the year, so we have to attribute that to the impact of last year's referendum."
He added: "So far this year we've seen another increase and it looks as if we are going to be close enough to doubling the number of passports this year compared with 2015, which was the last pre-Brexit year.
"So there has been a significant rise, not just in Britain but also in Northern Ireland."
He said 500,000 Irish passports were issued to applicants around the globe in the first half of this year.
"That's an extraordinary number of passports, well up on our previous numbers, which means that people around the world are looking for Irish passports in order to safeguard their position for the future," he added.
Mulhall went on to say that a hard border with Northern Ireland was "not feasible" and impracticable. He stressed the need for a flexible and creative solution.
"The clock is ticking now, time is moving on, and I suppose you're hearing a bit of urgency on our part, not least to have an Executive up and running in Northern Ireland so that they can contribute to this very important debate," he said.
The ambassador also said that Ireland ideally wanted the UK to remain in the EU customs union.
"I think people are now beginning to realize the complexities of leaving the European Union, and there's a debate developing here.
"We're making our position clear, which would be ideally we would wish Britain to remain in the European Union - that's not going to happen.
"We would like Britain to remain in the single market, that may not happen.
"But we think putting forward our view that remaining in the customs union would resolve many of these issues on the border of the isle of Ireland, that seems to us to be a practical solution."