The aftermath of the second televised UK leaders' debate has descended into a row over campaign leaflets.
The Tories and SNP have accused Labour of "deliberately lying" about their policies in leaflets and letters while the SNP demanded Labour withdraw leaflets claiming the Nationalists would cut concessionary travel.
Labour Holyrood leader Iain Gray hit back at the Nationalists, claiming Alex Salmond`s party had "sunk to low, dirty politics".
The row between the parties broke out after Labour's campaign leaflets sparked the most heated exchange of Thursday night's televised leaders' debate, with David Cameron branding them "pure and simple lies".
Tories deny planning to axe perks for the elderly, including winter fuel payments, free bus passes, free TV licences, free eye tests and free prescriptions.
Shadow Scottish Secretary David Mundell blasted Labour after one of Chancellor Alistair Darling`s campaign leaflets in Edinburgh attacked the Tories on family policies.
Mr Mundell said: "Gordon Brown says he did not authorise Labour's dishonest leaflets, which were deliberately targeting the most vulnerable people in our society, yet he himself issued one on free bus travel. Now his Chancellor has also resorted to fears and smears to scare young families."
He added: "Why are they deliberately lying on their literature? Are they prepared to say sorry for the leaflet lies and the disgraceful campaign that Labour has been running in Scotland? Will they now stop the dishonesty?
"Labour's election has been negative, dishonest and has been deliberately targeted at the most vulnerable people in our society, including the elderly, the low paid and families."
Meanwhile, SNP Glasgow East candidate John Mason hit out at Labour after the party launched an attack on the Nationalists over concessionary travel.
He said the SNP was extending the free bus pass scheme, adding it was "utter rubbish" to suggest this was being cut.
Mr Mason said: "If you cannot trust Labour on this, what can you trust them on?
"Labour must withdraw these leaflets now. They are needlessly scaring Scotland's pensioners in a desperate scramble for votes."
He added: "These leaflets are the worst kind of politics and Brown and his party should know better.
"Voters across the country have had enough of this kind of behaviour from politicians. Labour must destroy all these leaflets immediately."
Mr Gray, however, said SNP councillors in Fife had cut a concessionary travel scheme.
The Labour politician said: "Those 50p fares for travelling to Dundee, Edinburgh and Perth have been abolished by the SNP. It was Labour councillors who opposed that cut."
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