A campaign by Labour to regain the Falkirk West seat in the Holyrood election has suffered a setback.
Dennis Canavan plans not to contest his seat in the May election
James Lapsley - the former election agent of the outgoing MSP Dennis Canavan - has revealed he will back the SNP candidate for the constituency.
He has endorsed Michael Matheson over Labour's Dennis Goldie and has urged others to do the same.
Mr Goldie insisted that Mr Lapsley's decision would not affect Labour's campaign to win the seat.
Mr Canavan previously served as a Labour MP, but left the party to stand as an independent at Holyrood.
Mr Lapsley said Mr Matheson, who was elected as a list MSP for Central Scotland, had been a "fair and worthy opponent" over the last two Holyrood elections.
He said: "I know Michael Matheson has been an excellent list MSP working hard, serving the people of Falkirk and the people of Scotland diligently and conscientiously for the past eight years."
Mr Matheson said the endorsement was a "huge boost" to the SNP.
However, Mr Goldie said that Mr Lapsley was entitled to support who he wished, adding: "James Lapsley left Labour and he does not vote for the party."
Mr Canavan has a huge personal following in Falkirk West, where he has served both as an MP and MSP during the past 30 years.
He won the largest majority of anyone at Holyrood when he stood against the Labour Party and his decision to stand down at the May election has left many voters with a quandary over who to support.