Absolutely. When you 'threaten' to leave, in the same call they will offer you a deal. Reject it and end the call asking to have your account closed (it takes 30 days).
As long as you made the point that you really liked Sky but you just had to cut it for financial reasons, they will call you...
I was paying about 100 for the channels, sport, box sets, HD, broadband and phone.
Called up, said I was going to leave as I needed to start cutting my bills. Put the phone down.
They called back 2 days later and offered it all for £54 a month. I said yes.