Such cross-party co-operation has existed before, notably in the case of the 'three amigos' of the 1999-2003 Parliament (the Greens' Robin Harper, SSP's Tommy Sheridan and independent MSP Dennis Canavan). In that case, the aim was to ensure that these sole representatives of minor parties received a voice in the then new parliament, and couldn't be sidelined by the larger parties.
The advantage of this new group being formed seems to centre on the size of the group granting them a seat on the key Parliamentary Bureau, which sets the parliamentary agenda at Holyrood. The four main parties are all represented on this group, but the Greens have been denied access since they were reduced to two seats in the 2007 election. The formation of the group will also ensure its members more speaking time in debates and more opportunities to participate in First Minister's Questions.
The MSPs involved are the Green Party's Patrick Harvie and Alison Johnstone, elected independent Margo MacDonald, and the two ex-SNP independents John Finnie and Jean Urquhart. Finnie and Urquhart both left the SNP last month in protest against the party dropping its historic opposition to membership of NATO. The other ex-SNP independent in parliament, Bill Walker, does not appear to be involved. The group will hold the same number of members as the Liberal Democrats' group of five MSPs.
Although all five members of the group are pro-independence and broadly interested in social and environmental issues, they have been keen to stress that they will maintain their previous policy positions and there have been no changes in party membership by the creation of the group.
With the addition the new group, the composition of Holyrood now looks like this: