The leaders of the main UK parties have travelled to Scotland to urge voters to reject independence in the referendum.

Prime Minister David Cameron said he would be “heartbroken” in the event of a “Yes” vote, while Labour leader Ed Miliband said the case for the Union came from the “head, heart and soul”.

Scottish First Minister Alex Salmond said the leaders could not be trusted.

Meanwhile, a new opinion poll has suggested 47.6% of voters back “No”, 42.4% “Yes”, with 10% undecided.

The new poll, by Survation for the Daily Record, was conducted before the Westminster party leaders announced their campaign visits.

Mr Cameron and Mr Miliband abandoned their usual Prime Minister’s Questions session in the House of Commons to head north, after other recent opinion polls suggested the referendum race was now neck and neck.

Although the three leaders campaigned separately, they each called on voters to keep Scotland in the United Kingdom.

The three leaders have backed a plan of action spearheaded by former prime minister Gordon Brown, which they have said would see work begin on the handover of new powers on 19 September, the day after the referendum.

Speaking in Edinburgh, Mr Cameron – who Downing Street has confirmed will return to Scotland on Monday – said he was often asked whether his party would find it easier to win UK elections without Scotland, which currently has one Tory MP.

He responded: “My answer to that is, I care far more about my country than I do about my party.

“I care hugely about this extraordinary country, this United Kingdom that we’ve built together.

“I would be heartbroken if this family of nations that we’ve put together – and we’ve done such amazing things together – if this family of nations was torn apart.”