The original Government of Wales Act gave substantial powers to the assembly itself and its all-party committees in developing and implementing policies.

The new act will see Cardiff Bay moving to a Westminster-style system with government ministers framing policies while the assembly concentrates of scrutiny and legislation.

This is similar to the change seen in most Welsh councils over the past decade with a cabinet system replacing the old committee system.

This move is broadly supported by all the parties in the assembly who are frustrated that the assembly as whole is either blamed for or credited with policies that are originated by the governing party.

Assembly members (AMs) have been frustrated by the so-called "legislative log-jam" in parliament where assembly-prepared legislation has to compete for time with bills prepared by Whitehall ministries.

The new system would allow the assembly to draw up legislation following votes in the Commons and the Lords to approve the principal of the proposed measure.

For such a referendum to be triggered a broad consensus would be required in the assembly.

This clause in the bill is seen as crucial by AMs who fear that further devolution could be held up by Welsh MPs worried about a further erosion in their power and influence.