Seeing how it's a British News story, I think it's the Cooperative Party they are referring to. According to Wiki, they have a permanent partnership with the Labour Party. I think Socialist is more descriptive of their policies--you know evil things like Universal Pensions, Universal Health-care, Child Allowances, Unemployment Insurance, Worker's Comp and other Commie things. Sure glad they didn't catch on here.
Just teasing.
Regards Mike