The number of British citizens who are taking on the citizenship of another EU member state has risen substantially ahead of Britain's planned departure from the bloc in March, according to a survey conducted by German news service dpa.

Germany, Ireland, Spain and Portugal have seen a marked increase in applications for passports from Britons in the past three years.

Many Brits are anxious about their future and their ability to work or travel in mainland Europe as the outcome of Britain's negotiations with the EU on the terms of its departure and the economic impact of Brexit remains uncertain.

In Germany, this led a record 7,500 naturalizations by British citizens in 2017, up from a mere 622 in 2015. Ireland received approximately 183,000 applications for Irish passports from British citizens in 2018. The number of applications from mainland Britain, over 98,000, represents an increase of 22 percent compared to the previous year.

In Spain, the number of Britons who applied for citizenship tripled in the first 10 months of last year compared with 2015. The figure was nevertheless quite low, 166, owing to the requirement that a citizenship applicant from Britain renounce his or her current passport and prove residence in Spain for at least 10 years.

Portugal saw the number of citizenship applications from Britain skyrocket in the first 11 months of 2018 to around 500. In 2015, the tiny Iberian nation recorded only 62.

Britain's divided parliament plans to reopen its debate on Brexit on Wednesday, with a vote on a deal agreed by Prime Minister Theresa May and the EU scheduled for the third week of January. May's proposal is not expected to win a majority.