The former chief fire officer in Grampian has backed the Liberal Democrat candidate in West Aberdeenshire and Kincardine (WAK) as the race for the marginal north-east seat heats up.
David Dalziel, who retired from the fire brigade after the creation of the single Scottish Fire and Rescue Service, was chairman of the Better Together campaign group in Aberdeenshire during the referendum.
The Lib Dems are facing an uphill battle to retain the constituency, with the party trailing both the SNP and Conservatives in the polls.
The Tories are claiming it is a two-way fight with the Nationalists, and said Lib Dem voters are switching to their candidate, Alexander Burnett.
There have been mixed messages on tactical voting in the area, with unionists split on whether to back the Lib Dems or Tories.
Mr Dalziel, however, insists that Sir Robert Smith, who has represented the area at Westminster since 1997, remains best placed to defeat the SNP candidate Stuart Donaldson.
Mr Dalziel added: “I believe advice by some former members to vote Conservative is a well intentioned initiative to stop the SNP gaining ground but it is obviously flawed.
“To suggest that No voters in last year’s referendum should support the Conservatives in the WAK constituency when experts and pundits suggest they will be lucky to hold onto the one seat they have in Scotland risks splitting the No vote.
“Only Robert Smith, an experienced, popular and well respected figure, can attract the broad based coalition of NO supporters needed to stop the SNP in West Aberdeenshire and Kincardine. I urge NO voters to give him their support this time.”
Mr Burnett, however, believes the Lib Dems are not at the races.
He said: “Every independent poll in Scotland shows the same. Lib Dem support has collapsed. They have lost six out of every seven of their voters.
“There is only one party here in Scotland which is on the up and standing up for Scotland in the UK and that’s the Scottish Conservatives.”
Mr Donaldson, the SNP candidate, said: “Scotland can be stronger at Westminster than ever before with a big team of SNP MPs standing up for Scottish interests, and people in West Aberdeenshire and Kincardine can be part of this great opportunity by voting SNP.
“The SNP case is a positive one about what we can achieve for Scotland – we will leave the other parties to their negative campaigns.”