Blundering about

Does the Prime Minister know what he's doing?  The Independent reports:

David Cameron is to take the high-risk gamble of offering to hold a referendum on Scottish independence next year. He aims to call Alex Salmond's bluff by challenging him to stage a vote on Scotland's place in the UK within 18 months. 
...
The Prime Minister will publish legal advice that concludes the SNP administration in Edinburgh can hold a binding referendum only with the British Government's permission. He will say he is prepared to give his backing to a vote only as long as it is held by the summer of 2013.
...
Under Mr Cameron's move, the Government atWestminster would insert a "sunset clause" into the Scotland Bill, which is before the House of Lords, allowing the Scottish Government to hold the referendum in the next 18 months. But SNP sources said Mr Salmond was not prepared to enter in deals on a referendum and would veto Mr Cameron's "sunset clause" if Westminster tried to impose it on Scotland.

Even if (and it is a very big if, given the doldrums in which it currently finds itself) the Scotland Bill were to emerge from the legislative process in the form intended by Cameron, there is nothing to prevent Salmond ignoring it and proceeding with a so-called advisory referendum at a time of his own choosing.  Furthermore, by seeking to impose a London diktat on the Scottish political process, Cameron is more likely to hasten the outcome that he seeks to avoid.