I have generally been against the idea of a salary cap in the Premiership. why? because I was under the impression that it would dilute the quality of the league. If players know that they cannot obtain a certain wage here then I feel it is inevitable that they would play their football elsewhere. At the moment I believe the English league to be one of the most exciting leagues in the world and arguably we have the strongest "top four teams" in Europe. Introducing a salary cap may destroy this as players may not be inclined to play in the UK especially if countries like Italy and Spain still had the option for negotiated salaries based on no cap.
However since the sorry Portsmouth saga I have been gradually changing my view. Portsmouth have payed huge amount in transfer fees yes, but they have also been handing out large weekly wages to the likes of Defoe, Muntari, Glen Johnson and Crouch. If for example there had been a salary cap and the players within "the big four" were at the limit i believe the players at Portsmouth wouldn't have been getting so exorbitant payments; as they really couldn't justify being payed the same as a top four club in wages. I believe it would bring a hierarchy to football in terms of pay that would offer better stability - if you are within the "top four teams" then being nearer the wage cap would seem conceivably fair as their income would be higher due to Champions League etc, other players for "smaller" clubs then couldn't hold so much clout to demand high wages.
Another reason why I have changed my view is the following article:
Vast wages at the heart of Premier League's £3.5bn mountain of debt| David Conn | Sport | guardian.co.uk
Essentially what the article states is that the English league is the most lucrative but is also saddled with the most debt, more than ALL of Europe put together

. This is totally unacceptable IMO and something needs to be done, perhaps a salary cap doesn't go far enough - limit the amount of money teams can spend on transfers based on the turnover perhaps? Even if a salary cap was to be introduced what level should it be set at? £20,000 a week? That is another issue which would spark debate.
What are your opinions on the issue, I simply think the way football is going in about 20 years time some top flight clubs that we see today will simply have gone liquidation if things continue and fans will be left to pick up the pieces, thoughts?