So, if you listen to the latest podcast, Gavin is his usual self and knows more about our politics than his own.
It is true that in Britain, elections can really happen whenever. There are proposals on the table to make it a regular 4 years, and here's why:
The Prime Minister has power to dissolve parliament whenever, the Queen is just a formality, and there is no real authority behind that. He can do it if he sees his party in a particular period of strength, and sees an opportunity to capture additional seats.
Also, the PM is not elected. Instead, he is chosen by the party as its leader, and if his party is the ruling one, he is PM. The head of the other party is the head of the opposition.
Finally, the need for a coalition is not exactly the same as Ross Perot and the Clinton election, because that was a presidential election, which as stated the UK doesn't have. It comes from the fact that Britain is a three party state, not a two party state. Thus, it is possible for the smallest party to be the spoiler, as the Lib Dems were here, forcing the need for a coalition to have a working majority.