Positive discrimination isn't something that one would normally link with the centralisation of power. Yet this has been its strange partner.
In the name of making their parties 'look more like the Britain they represent' both Labour and now the Tories are going to enourmous lengths to force women and ethnic minorities into Parliament.
However, for both these parties, sexual or race equality was never their real agenda. They simply used this argument as cover from their primary goal: to centralise power and to strip if from local associations.
Thus when Tony Blair was seeking to reign in infamously indisciplined local labour branches, he removed all their power. Of course his reason for doing this was so that more women could be elected (something every ambitious politician in the party agreed with). It just happened to be a happy side effect of exactly the same party reform that local members lost almost all power over who they selected as their MP. If they made the 'right' decision then they were left alone but if they didn't agree or if an already elected MP disobeyed the leadership, then they were simply over-ruled. This new deselection process is the real reason Labour MPs have been so cowed for the last 9 years; and why they have stopped performing their constitution role of scrutinising the Executive. They know they have the freedom to speak out, but only at the expense of losing their seat at the next election. Especially for Labour MPs, this is a scary threat as most of them have never earned anything approaching an MPs salary or are likely to elsewhere.
Now the Tories jump on the centralising bandwagon too. The fact that there are two few women as candidates is used in true Stalinist style as proof of discrimination. Cameron now uses exactly the same logic to defend his centralisation of MP selection that Gordon Brown uses for his attacks on Oxford and Cambridge admissions. In both cases, the possibility that merit or other social factors might be contributing to the discrepancy is ignored. The local administrators are first slurred as racists/sexists/bigots and then this is used as an excuse for taking away their power.
Meanwhile the press looks on approvingly. Nobody seems to be pointing out that discrimination is wrong; that positive discrimination is still discrimination; and that two wrongs don't make a right.