Prime Minister heads north of the Border to step up fight in defence of the Union Published on Monday 16 April 2012 01:07 PRIME Minister David Cameron is set to make his third campaign visit to Scotland in the run-up to the local council elections, it was reported yesterday. Mr Cameron used his last visit to Scotland, earlier this year, to offer a deal that would see the ballot in the independence referendum, which the SNP wants held in 2014, restricted to a single question on independence in return for a promise of more powers after a vote in favour of the Union. A Conservative source said that Mr Cameron was "passionate" about the anti-independence campaign and wanted increasingly to take the fight to the SNP in the run-up to the referendum. Mr Cameron's planned visit ahead of the 3 May local elections in Scotland, came as Deputy Prime Minister Nick Clegg warned of a threat to Scottish business unless the SNP brought forward the preferred 2014 referendum date. The Liberal Democrat leader said the SNP had "talked in whispers" about independence during last year's Scottish Parliament election campaign. He called for the referendum to be settled before 2014 "for the good of encouraging investment and economic stability." Mr Clegg said: "Last May an SNP victory made a referendum on independence likely. The Scottish Secretary, Michael Moore, has been working to make it possible for the Scottish Parliament to hold a fair, decisive and legal process. Sooner rather than later, that will allow us to move on to deal with further devolution across the UK and with the economic importance across the UK and with the economic issues, which are just as important to the hard-pressed families, young people and pensioners of Scotland. Mr Cameron is expected to use his latest visit to Scotland to promote his party's local elections campaign and to attack the SNP for using the campaign as a springboard for independence. Scottish Conservative leader Ruth Davidson has claimed that the Nationalists are trying to turn the local election campaign into a dry run for the independence referendum. That claims is denied by the party. The SNP's local government campaign director, Derek Mackay, defended his party's approach. He said that independence would deliver a "fairer and more prosperous" Scotland. Mr Mackay, who is also Scotland's local government minister, said: "The elections on 3 May are about local jobs and local services - SNP candidates and their teams are working extremely hard and speaking to more people in every community in Scotland than ever before in a local election. The SNP enters the campaign with a strong record and a powerful vision for a better, fairer and more prosperous Scotland.