How will Brexit affect Northern Ireland?
After several delays and legal arguments, Britain has officially informed the European Union that it wants to withdraw from it, after a majority of voters chose 'Leave' in last summer's referendum.
But two parts of the United Kingdom - Scotland and Northern Ireland - had more people vote to stay in the EU, than to leave it.
Scotland's political leaders are now calling for a referendum to leave the UK, and in northern Ireland the idea of rejoining the Republic of Ireland is up for debate.
Don Duncan reports from Northern Ireland.