"Speaking to influential ministers and aides I get the impression that their favoured month for an election is next April. In theory they could hold out until June, but that would mean going to the country in the immediate aftermath of the May local elections when Labour is expected to do badly. This option is already ruled out. There will be no June election. Obviously a general election could be held on the same day as the May local elections and it is still a likely option. But that date is the equivalent of going right up against the buffers when the media and perhaps voters will be getting impatient."
The likelihood of an April election strengthens the wider theme of Richards' column: that there's not much time left for the parties to refine their pre-election messages. After the Christmas recess, MPs will devote much of their time to preparing for the Big Day, and they'll want their campaigning themes in place by then. From the Tories' perspective, it means that what Tim Montgomerie is calling David Cameron's "look-in-to-the-camera moment" needs to come sooner rather than later - some time between, say, the start of the Tory party conference and the immediate aftermath of the Pre-Budget Report.