> - Why does Corbyn's opinion matter? Well back when Cameron did a deal with Clegg, they did a fixed terms act, meaning elections had to happen every 5 years. This one is within 5 years of the previous, so you actually need a two-thirds majority in Parliament to trigger it.

May says she'll call an election under the Fixed-Term Parliaments Act, and obviously that's the first choice, but now that the Tories are governing without the Lib-Dems, they can also simply repeal the Act (with an ordinary majority).