The number of people trying to get Irish passports surged in 2018 - here is how to get one

If one of your parents is Irish, you are also eligible to become a citizen (keep reading for how to apply.)

Your grandparents can come in handy too. If one of them is an Irish citizen who was born on the island of Ireland (that includes Northern Ireland), you are entitled to citizenship — regardless of where your parents were born.

If you're going down the ancestry route, you'll need to sign up to the Foreign Births Register, more details of which can be found on the Republic of Ireland's Foreign Affairs website.

That involves providing a number of documents, including your parents' or grandparents' longform birth certificates, and a current form of I.D.

You are also entitled to Irish citizenship if you are married to an Irish citizen. There are a few conditions:

• You must be married to an Irish citizen for at least three years
• You must have had a period of one year's continuous "reckonable residence" in the island of Ireland immediately before the date of your application (that includes Northern Ireland.)
• You must also have been living on the island of Ireland for at least two of the four years before that year of continuous residence

If you've lived in the Republic of Ireland permanently for five of the previous nine years, you can apply to become a "naturalised" citizen. You need to be over 18 and have "good character." Mostly, this involves not having a criminal record.

Ireland has a "naturalisation residency calculator" which helps you work out whether you've spent enough time in the country over the last five years to qualify.

You can find the naturalisation application form here.

The application process for to become an Irish citizen isn't cheap. It costs £150 ($190) to apply, and £835 ($1060) for the full certificate. Given all the benefits of EU citizenship, however, that might seem like a small price to pay.

Any person who was born in Irish airspace is automatically entitled to full Irish citizenship, regardless of their parents' nationality. According to the Irish Citizens' Information Bureau, "A person born in Irish sea or air space to a foreign national on a foreign ship or in a foreign aircraft" is entitled to citizenship.

Now you wait. The application process to become a citizen can take 18 months to complete.

Once you've done that, you can apply for a passport, which usually takes six weeks. You can get a passport application form from your nearest Irish embassy or consulate.

The embassy in London is in Grosvenor Square, and a list of others can be found here.

The Irish Foreign Office provides a step-by-step guide to applying for a passport on its website.