The number of Irish passport applications from British residents refused last year is understood to be in “double digits”.
The Department of Foreign Affairs received 80,752 applications from British residents last year, according to figures released by Tánaiste Simon Coveney.
A total of 65,678 passports were issued through the Irish embassy in London,
The Department said that while the difference is 15,074 not all applications are submitted through the Irish embassy.
In 2016 a total of 63,453 British residents applied for passports. The Irish embassy in London issued 63,452.
The difference that year was just one passport fewer than the overall number of applications from British residents.
Tánaiste Simon Coveney told Social Democrats TD Catherine Murphy in reply to a parliamentary question that the Passport Service does not compile data on the number of applications refused but that in general it was "small".
Sources in the Department of Foreign Affairs said the number of refusals was in “double digits”.
Mr Coveney said that all passport applications had to meet the requirements of the amended 2008 Passport Act. “Section 12 of the Act, makes provision to refuse a passport in certain circumstances.”
He said that “in all cases, the Passport Service must be satisfied as to the identity of the applicant and that the applicant is an Irish citizen”.
Where applications were incomplete, applicants would often be contacted for clarifications or requested to provide further documentation.
Difficulties can also arise in applications for minors.
“All guardians must provide consent for a minor’s application or if unavailable or unwilling, submit a court order as appropriate,” Mr Coveney said.
Worldwide, the number of applications for Irish passports received from outside the State surged from 190,905 in 2016 to 227,223 last year and up to the end of September this year had hit 191,271.
Mr Coveney said that in the 18 months since the online passport application service was launched in March last year 270,187 passports were issued using this procedure.
Overall hundreds of thousands of UK residents have applied for Irish passports since Britain voted for Brexit and the rate of applications continues to increase.
Statistics supplied to Fine Gael Senator Neale Richmond by the Irish Embassy in London show that the number of passport applications from the UK has risen significantly since the year before the Brexit vote.
In 2015 there were almost 99,944 applications from Britain and Northern Ireland, a figure that rose to 131,035 the following year. In 2017 there was a further increase of over 30,000 applications to 163,026.
And figures this year to the end of May show 91,860 applications were made.
The number of people from the North who applied for an Irish passport rose from 53,715 in 2015 to 67,582 the following year.
Applications jumped again last year to 82,274 and up to the end of May this year 46,898 people in the North applied for Irish passports.
"Embassy officials predict that based on this, 2018 will be the busiest year so far for Irish passport applications in the UK," Mr Richmond said.
People born to Irish parents or grandparents are entitled to apply for an Irish passport through a claim to citizenship.
“At least 10 per cent of the UK’s population, not including Northern Ireland, are estimated to qualify for an Irish passport and in light of Brexit” many were “staking their claim” to the passport, Mr Richmond said.
Mr Richmond said that “while many in the UK are concerned with the looming disaster of Brexit, we must seize the positives from this new wave of people reconnecting with their Irish heritage, our post-Brexit UK-Irish relations can be built on a strong, connected diaspora”.
In contrast, applications from the Irish diaspora elsewhere around the world have dropped slightly.
Ms Murphy noted that the number of applications has fallen annually since 2016 in locations with significant Irish populations including New York, San Francisco and Boston in the US although there has been an increase in applications to the Chicago consulate from 1,126 in 2016 to 2,046 last year and 1,435 up to the end of September this year.
Applications outside the EU are also falling including those from Canada, New Zealand, Australia, United Arab Emirates, China and Japan.
In Africa, applications from Nigeria, Mozambique, Uganda, and Tanzania have also fallen. In Kenya, there were no applications in 2016 or last year but four this year.
This article was changed on October 30th, 2018 to reflect clarification received from the Department of Foreign Affairs on the reason for the difference between the number of British applications for passports and the number of passports issued by the Irish Embassy in London.
