What do you get if you put an Englishman, an Irishman, and a Welshman on a boat bound for Dublin? Griff Rhys Jones, Dara O Briain and Rory McGrath return for the fourth series of Three Men in a Boat, and this time the trio are making their way across Ireland via canal and river, taking in the sights on their way to the famous Limerick Poetry Festival. With Irishman Dara obviously nervous that Griff and Rory's behaviour (and in particular their terrible Irish jokes) will embarrass him up on home turf, his two companions are in their element. They see the trip as a perfect opportunity to irritate Dara while exploring Ireland's off-the-beaten-track midlands. Kicking off in Dublin, the Three Men are soon heading down the Grand Canal on Ireland's last original Guinness barge. They are only slightly hampered by the fact that it's over 80 years old, very heavy and somewhat difficult to start and even more difficult to stop. It has no brakes or reverse gear. The barge's lack of speed, temperamental engine and an endless succession of canal locks prove too much for Three Men and they quickly abandon it to take to the Royal Canal in a car with a difference... The Three Men are more than a little surprised to be greeted in Mullingar (Ireland's geographical centre) by a huge street parade complete with marching band, cheering children and food fayre - how will they cope with all the attention? By the end of the episode it's all gone to the dogs as the boys turn out to see Dara's greyhound, Snip Nua, take part in a race. Part of the BBC Christmas 2009 season.