HIGH-PROFILE campaigns to encourage tactical voting in a bid to counter the SNP surge fell flat on Thursday, with numbers uniting behind unionist candidates proving woefully insufficient in preventing a nationalist landslide.

While it had been speculated that Scottish Labour leader Jim Murphy could hang on to his East Renfrewshire seat on the back of votes lent from Conservatives, he ended up losing by a margin of almost 4,000.

The Conservative vote reduced by around 3,000 on 2010 levels, suggesting some Tories had been willing to back Mr Murphy, but not in nearly large enough numbers to prevent his defeat.

The Scottish Liberal Democrats, the party that had called most loudly and explicitly for tactical voting in the 11 seats it held, saw its key strategy backfire. Party strategists had insisted that the tactic could lead to it holding on to several seats. However, in the end just Alistair Carmichael retained, sneaking by in Orkney and Shetland with a vastly reduced majority of just 817.

The party had believed that tactical voting could lead to a victory in Gordon for Christine Jardine who was battling Alex Salmond. On the night, however, the former First Minister swept home with a majority of more than 8,000. The LibDem vote in the constituency increased by around 1,500 compared to 2010, however the vote for the SNP rose by around 17,000.

Some right wing newspapers had produced tactical voting guides in an attempt to prevent SNP victories while some voluntary groups sprung up and attempted to organise co-ordinated efforts among unionists.

Polling expert John Curtice, Professor of Politics University of Strathclyde, said that only one seat in Scotland - Edinburgh South which was retained by Labour's Ian Murray - could be seen as one in which tactical voting played a decisive factor.

He said: "It had about as much impact as we expected - not a lot. It's not impossible to believe that the Edinburgh South constituency was saved by tactical voting. In Dumfriesshire [where sole Scottish Tory MP David Mundell hung on] the LibDems did so badly that it's difficult to prove it was a decisive factor. In Orkney, we expected them to hold on.

"It was only ever possible that it would save a handful of seats, and was never going to stop a nationalist tsunami. When a party gets 50 per cent of the vote - and the SNP did - it's won. End of story."