Two more unions threw their weight behind Neil Findlay and Katy Clark yesterday in their bid to become leader and deputy leader of the Scottish Labour Party.

RMT, which is no longer affiliated to the party, took the unusual step of declaring support for the left-wing "dream ticket" because the pair have been active in supporting the union's work in Holyrood and Westminster.

"Both Neil Findlay and Katy Clark are strong supporters of public ownership and trade union and employment rights and it is clearly in the interests of the working class that they succeed," said the union's general secretary Mick Cash.

"We wish them every success and stand ready to assist their campaigns."

Meanwhile support from the Musicians' Union put the pair firmly in the lead among Labour affiliates.

Mr Findlay said: "I'm delighted that my candidacy has been endorsed by those representing workers across the board: public and private sector, manufacturing, service, finance and now culture."

But shopworkers' union Usdaw declared its support for rightwingers Jim Murphy and Kezia Dugdale late on Tuesday evening.

The committees of Scottish Young Labour and Scottish Labour Students voted to follow suit, though the University of Aberdeen's Labour Club broke with this to support Ms Clark.

Another affiliate, the Socialist Health Association, also announced its support for Mr Findlay and Ms Clark.

Members of affiliate organisations vote as individuals, and their votes make up a third of an electoral college that also enfranchises party members and parliamentarians.