PRIME Minister David Cameron last night angered the Scottish Government by attempting to lay down a new timetable for setting details for the independence referendum.

The Prime Minister came to Scotland yesterday and visited a construction yard in Fife which had won fresh North Sea orders. He then visited Glasgow, which is bidding to host the next Youth Olympics. It was then Mr Cameron chose to engage in the constitutional debate.

The Prime Minister added to the row over the way an independence referendum would be conducted, appearing to demand a deal with the Scottish Government by September on the details of the referendum.

He challenged First Minister Alex Salmond to gamble all, using the phrase "let's go nap" – a phrase used by gamblers to define betting everything on the table.

Mr Cameron said: "I hope we can do it quickly. I mean frankly the Scottish people deserve to have that fair, decisive and legal referendum. We made an offer to let that happen.

"The Scottish Secretary of State and the First Minister should be hammering out the detail so I can meet Alex Salmond at the end of September and then we can go nap on a date and all the rest of it.

"It really should be possible to do this.

"All of the Scottish political parties, both campaigns, want a one question referendum that is what the Scottish people deserve.

"Let's for heaven's sake not let process get in the way of the outcome the Scottish people deserve."

However, the Scottish Government responded last night in the most dismissive terms, saying: "As we have always said, we have absolutely no objection to a Section 30 Order in regard to the referendum, with no Westminster strings attached – which could be agreed very shortly.

"The terms and timing of the referendum must be decided in Scotland, by the Scottish Parliament – not dictated by a Tory-led Government at Westminster – and the Prime Minister has already conceded the autumn 2014 timescale.

"We are very confident indeed of achieving a Yes vote for independence in autumn 2014.

"The Scottish Government's referendum consultation received nearly 10 times the number of responses of the UK Government consultation, and the independent analysis will be completed and published by the end of the summer.

"As the First Minister said in his letter to the Scottish Secretary last month, Bruce Crawford for the Scottish Government and Scotland Office Minister David Mundell have already had two meetings to help clarify the procedural issues which need to be considered in any wider discussions on the referendum. They are due to meet again in August to see what further progress can be made."

Scottish ministers are holding to the position they have the Holyrood mandate for any changes to the future powers of the Scottish Parliament, but Westminster remains sovereign on any changes to the devolution settlement itself.

The key is that Scottish ministers can press ahead with a referendum in 2014, but under Westminster rules this would have no standing.

Mr Salmond argues this does not matter as all referendums are consultative.

A referendum can be put on a more formal footing under Westminster law, and this has been held out as a possibility to Scottish ministers if they can accept conditions on the number and wording of questions.

Yesterday's comments from the Prime Minister can be seen in that context, and are as likely to be resisted as previous attempts to dictate the terms of the referendum.