Cameron to head to Scotland

The British prime minister on Monday was expected to use his second visit to Scotland in the past five days to make an impassioned plea for Scots to vote no to independence, when they go to the polls in Thursday's referendum.

First Minister Alex Salmond was also expected to be out on the campaign trail in a final push to put the pro-independence campaign over the top.

With less than four days to go until the referendum on Scotland's future, opinion polls indicated that the outcome of the vote remained too close to call.

An Opinium survey conducted for the British Sunday paper the Observer put the "no" side ahead on 47.7 percent support, compared to 42.3 for the "yes" campaign. It also put the undecided vote at 10 percent.

A survey taken by the firm Panelbase and published by the Sunday Times gave the anti-independence camp 50.6 percent support, with 49.4 percent of respondents supporting independence.

However, an ICM opinion poll conducted for the Sunday Telegraph gave the "yes" side a sizeable lead with 49 percent, compared to just 42 percent for the "no" campaign. Similarly to the Opinium survey it put the number of undecided voters at nearly 10 percent, although pollsters cautioned that it wasn't clear if the sample size of this survey was large enough to be representative.

Meanwhile, British media have reported that Queen Elizabeth has made her first comment on the referendum.

"Well I hope people will think very carefully about the future," Britain's head of state is reported to have told an onlooker on Sunday, after attending church near her Balmoral estate in the Scottish highlands.

While some may interpret the comment as a warning to Scots not to sever their more than 300-year-old union with England, the queen did not clearly express support for either side, maintaining the political neutrality that is required of her under the UK's constitution.

If voters do choose independence on Thursday, the vote is to set into motion 18 months of negotiations on the terms of Scotland's exit from the United Kingdom, which would occur in early 2016, 309 years after Scotland joined England in the union.

pfd/mg (AFP, AP)