One of my favourite regular pieces in Private Eye is "An Apology", where it spoofs an editorial line explaining a 360 degree turn in it's attitude towards something and/or someone out of some form of vested interest.
Recently one could forgive some Labour Party members for taking such a view towards The Daily Mail because, in case anyone hasn't noticed, it is a paper less hostile towards Brown's premiership than it is towards Blair's.

But it should be recognised that being less hostile does not mean pro-Labour. Paul Dacre and Gordon Brown may be dining chums but friendships across the political divide does not change viewpoints so much as personal attitude. It's rare, but some PM's and leaders' of the opposition have been friends, although not above attacking each other in the House of Commons. Note Churchill/ Attlee, Wilson/Thatcher, Kinnock/Major, and Smith/Major.
So I think it's fair to welcome The Daily Mail being a bit less hostile, but equally to recognise that it is a right-wing newspaper and one that can be unpleasant. If one wants to see the Mail as a friend then fine, but friends should point out when they think you are going a bit far!
So I think that it's best to treat this new "friendship" with gentle caution, rather than an overfriendly or hostile response. After all a Labour-friendly Mail may be a compromise too far, but a respectful opponent may be beneficial to both sides.