A claim in Scottish Conservative election literature that Labour and the Liberal Democrats no longer oppose independence is 'a lie', Scottish Labour have said.

The Conservatives have been broadcasting the claim online and on official campaign literature delivered to Scottish homes for a number of months.

In February, Lib Dem blogger Caron Lindsay wrote of a campaign leaflet she had received in the style of a letter from Ruth Davidson which made the same claim: "Labour and the Lib Dems have dropped their opposition to independence".

The Tories used various newspaper headlines in a clippings style to show how the position of Labour and the Lib Dems on independence had softened, citing statements made by Kezia Dugdale and Willie Rennie that their party colleagues would be free to campaign for independence if they wished.

Labour pointed out the "lie" and also mocked the Tories for not being able to "bring themselves to use the word 'Tory'" in their election literature.

The Conservative campaign has sought to put Ruth Davidson front and centre, with the message "Ruth Davidson for a strong opposition" prominent at the party's manifesto launch and in campaigning.

A Labour spokesperson said: "It's amazing that the Tories have time to lie about Labour on a leaflet when they can't even bring themselves to use the word 'Tory' on them.

"Ruth Davidson is on the record supporting a second referendum if the SNP win the election whilst Labour's manifesto opposes a second referendum for the next five years.

"Rather than rerun the arguments of the past Labour wants to look to the future to use the new powers to tax the richest 1% so we can invest in schools and stop the cuts to public services.

"The Tories will stand by and let the cuts happen, whilst planning hidden taxes on the sick and on learning."

The Conservatives hit back, claiming that Labour leader Kezia Dugdale was "comfortable" with party colleagues backing independence.

This comes after reports earlier in the week that a Labour candidate who supports independence said at a hustings that Kezia Dugdale was "comfortable" with the notion, and predicted "a lot of soul searching" for Scottish Labour on the constitutional question.

A spokesman for the Scottish Tories said: "It's astonishing Labour would want to draw attention to its own weakness on independence in the week it emerged Kezia Dugdale is 'comfortable' with with her candidates backing independence."

"This after she said she could even see herself voting for the break-up of the UK in future."

The Scottish Lib Dems said the Tory claims were "laughable".

A Lib Dem spokesman: "This is laughable from a party who put short-term political advantage before the long term interests of Scotland and the Scottish people after the referendum.

"This is a desperate attempt to distract from Ruth Davidson's support for George Osborne's assault on disability benefits, and her plans to cut taxes for the rich and services for everyone else."

STV reported on Monday accusations levelled by Murdo Fraser of the Scottish Conservatives that Labour were lying in election leaflets over council tax.

The SNP and the Scottish Greens have also been approached for comment.