The old Clause 4 was written in 1918 from what I can see. We may need a knowable LP member to put us right on this, but that may be why it's clunky Bridgeit.
Blair and the party under him were "democratic socialists" (which sometimes seems to be interchangeable for social democrats and sometimes not). The LP under Blair changed the old Clause 4 I quoted to this in 1995.
The Labour Party is a democratic socialist party. It believes that by the strength of our common endeavour we achieve more than we achieve alone, so as to create for each of us the means to realise our true potential and for all of us a community in which power, wealth and opportunity are in the hands of the many, not the few, where the rights we enjoy reflect the duties we owe, and where we live together, freely, in a spirit of solidarity, tolerance and respect'.
Dates, etc., are thanks to Wikipedia so I am sure someone will have more detail than this.