Labour needs to rediscover its sense of purpose and represent "a better Scotland", the party's last first minister has argued.

Lord McConnell, who was first minister for more than five years until the SNP won power at Holyrood in 2007, said the party had become "a political machine that is angry about what has happened in Scotland in the recent past".

Instead of just attacking the SNP - which will be led by Nicola Sturgeon when Alex Salmond steps down next month - he called on Labour to focus more on setting out its own policies and priorities.

He also warned the forthcoming appointment of Ms Sturgeon - who he regards as more left wing than Mr Salmond - could make the challenge that the party is facing more difficult.

He told The Times newspaper: "I joined the Labour Party because it was a movement. My loyalty over years has not been to a party structure, it has been to a cause.

"In all the ups and downs I have had, the thing that has kept me going is a belief in a better society. The Scottish Labour Party needs to be a cause. It needs to represent the future and a better Scotland."

He spoke out as a new group of Labour activists, who want the party north of the border to make radical changes, held their first meeting.

The Labour for Scotland group wants the party to consider changing its name to the Independent Labour Party, and also supports Holyrood being given full control over income tax, as well as complete responsibility for welfare - a position which goes further than Labour's existing plans for further devolution.

It states the party should pledge not to work with the Conservatives in any future Scottish independence referendums or ''any other party whose policies are fundamentally at odds with the views of people in Scotland''.

Scottish Labour must be ''fully autonomous from its London leadership'', it argues, suggesting the party north of the border should have the right to appoint its own full-time officials and write its own constitution.

Meanwhile Lord McConnell described the state of the party in Scotland as "very sad for Labour but more importantly it's very sad for those we represent".

He claimed senior figures in the party "have found it far too difficult to get over their anger at losing, their anger at Alex Salmond being first minister, their anger at the media for not holding the SNP to account enough, their general anger at the state of the world".

He added: "What we haven't had is an expression of what Scottish Labour stands for as we move through the 21st century. What is our purpose? Why should people support us? Why should we want to be the Scottish Government?

"We must rediscover our sense of purpose, our vision for Scotland, our ability to stand up and articulate the concerns of the people we most represent. We need policies and ideas that reflect that - and we're running out of time."

He said while Mr Salmond was "essentially a right-wing populist posing as a social democrat" Ms Sturgeon "is a social democrat".

Lord McConnell added: "So if we've had a challenge of the last few years (her) election changes that dynamic even more. She is a post-devolution politician who is positive about the parliament, and Scottish Labour needs to be very aware of the scale of the challenge it now faces."

After the Labour for Scotland meeting, Councillor Jonathan Findlay, who was one of the speakers, said: "This was the start of a vitally important conversation about the future of the Labour Party in Scotland.

"The turnout exceeded our expectations and it is clear that there is an ambition within the party for radical and progressive policies that will make Scotland a fairer and better country.

"All sections of the Labour Party were represented at today's meeting, with people from the trade unions, local government, the co-operative movement and constituency activists.

"The speakers urged, and the meeting agreed, that Labour for Scotland should continue as a platform for discussion and debate within the party and we will be announcing more events in the coming days, including a meeting at Holyrood for interested MSPs."

He added: "We want to support and empower the leadership of our party to take forward an agenda for home rule in the 21st century that will capture Scotland's imagination and ultimately change people's lives."

But SNP MSP Sandra White said: "While Labour tears itself apart over its alliance with the Tories, and the whispering campaign against Johann Lamont continues, the SNP is going from strength to strength.

"Lord McConnell said today that the Labour Party has to remember that it should be speaking up for poor and disadvantaged people - but the idea that a party which worked hand in glove with a right-wing Tory government intent on attacking some of the most vulnerable people in society can ever truly represent disadvantaged people is absurd.

"This is exactly why Labour's poll ratings are tumbling - and why more and more people in traditional Labour heartlands are switching to the SNP."