Minister for Foreign Affairs and Trade Charlie Flanagan has apologised for the use of a four-letter word in a Twitter exchange with Sinn Féin TD Pádraig Mac Lochlainn yesterday.

Mr Flanagan used the word after Mr Mac Lochlainn posted a picture of a group of Blue Shirts, a precursor movement to Fine Gael.

A spokesman for the minister said this evening that Mr Flanagan was an active user of social media but apologised for any offence caused by his exchange.

Mr Flanagan first tweeted: "2015 offers Ireland the choice of Constitutional politics or Cult politics."

Mr Mac Lochlainn responded with the picture and said: "Hopefully cult politics doesn't make a comeback".

Another tweeter commented: "think that was a spelling mistake", with the minister responding: "yep left out the 'n'."