Quote Originally Posted by rory_20_uk
If not directly the Monarch saying in extremely rare cases "No", then I feel that having the legislation placed for review by a royal Commission should be possible.
Theoretically this is possible, even under the settlement of 1688. However, it would need an Act of Parliament to derogate to a Royal Commission and provide the powers of review to that commission. Currently (you guessed it) only the PM can set up a Royal Commission.

In addition, this is what the House of Lords is supposed to do as the second chamber. Even stuffed with pork barrel appointees it still does on occasion.

But with the Parliament Act, all these avenues can be overruled. The constitution would need to be refined to make these minor irritations into a genuine system of checks and balances. But since the PM would be changing the constitution to reduce his powers, its not very likely to happen, methinks.

As it is, the British Prime Minister has all the powers of an unrestrained monarch. Parliament is supposed to be there to hold the executive to account, but with the party system being as it is, there are precious few checks on his almost absolute power, save a tedious election every four or five years. (And he even gets to choose when that will be!)