SCOTTISH Labour leadership hopeful Ken Mackintosh has fired the first shots in the battle to replace Jim Murphy, as it emerged that anyone will be able to vote in the contest for £3 if they register as a party supporter.

The long-serving Eastwood MSP insisted he could defeat frontrunner Kezia Dugdale, saying she was not yet experienced enough to lead the party as he distanced himself from Mr Murphy, with whom he shared an East Renfrewshire constituency office.

Mr Mackintosh, who is standing on a platform of offering a more constructive form of opposition to the SNP, said: "The reason that Jim and I worked so closely together is that actually we were opposites, we were sort of Yin and Yang.

"My kind of politics is entirely different. I have got no interest in Westminster and never have done. I'm not interested in that kind of power politics whatsoever."

Nominations for both the Scottish Labour leader and deputy leader positions open today, with Ms Dugdale and Mr Macintosh so far the only candidates for the top job and several vying to become second in command.

The party's finance spokeswoman Jackie Baillie is believed to be preparing to declare her candidacy for deputy leader, while Alex Rowley, the Cowdenbeath MSP who quit the party's frontbench team last month and called for Mr Murphy to resign in the wake of a catastrophic general election defeat at the hands of the SNP, is also seen as a contender.

Glasgow Council leader Gordon Matheson is understood to be considering running for the deputy leadership, as is Stephen McCabe, the leader of the local authority in Inverclyde. Speculation has been mounting for some time that Mr Matheson sees his future at Holyrood while Mr McCabe has a high profile within the party, currently holding a place on its executive committee.

Under reforms which Mr Murphy pushed through in his last act as party leader, councillors are able to stand for the deputy role for the first time. It would offer them a place at the top of regional lists for Holyrood, a position seen as hugely valuable after the automatic right of sitting MSPs to retain their status on lists was removed and with Labour facing an uphill struggle in constituencies next year.

The leader and deputy leader will be elected for the first time on a one-member, one vote system. Meanwhile, acting leader Iain Gray has said anyone can vote in the contest by registering as a "party supporter" for £3.

Mr Gray said: "These radical new reforms will set Labour back on the road to regaining the trust of the Scottish people. I want as many people as possible to join us on that journey, which is why these new reforms will make it easier for supporters to get involved."

Elected Labour politicians have until Friday to declare their candidacy, with the new leader and deputy leader to be announced on August 15.

Meanwhile, the deadline for parliamentary nominations for the UK Labour leader is at noon today. Shadow ministers Andy Burnham, Yvette Cooper and Liz Kendall are expected to secure the 35 nominations from MPs required to stand, while left winger Jeremy Corbyn is likely to fall short. Mary Creagh, the shadow international development secretary, has pulled out of the race.

Ms Cooper will give a speech in London today and announce a drive to end child poverty within a generation. The MP will say that after Labour made huge strides in reducing child poverty between 1997 and 2010, it is on course to rise to 4.7 million by 2020 under the Tories.

The shadow home secretary, who is third favourite behind frontrunner Mr Burnham and Ms Kendall to win the contest, will say: "Holding back so many of our children will limit our economy, divide our communities and store up social problems for the future. And it's just wrong for so many children to be denied the best start in life. I want a Britain in the 2020s which is lifting children out of poverty and helping them on not knocking them back."