A Question was asked in the House of Lords about the Scrutiny Reserve on European legislation. This has been defined (by the Foreign Office) as
"an undertaking by the Government not to agree to a measure in the Council of Ministers if Parliament has not yet completed its consideration of the proposal, unless there are special reasons for doing so (e.g. where the national interest would be damaged by delaying agreement)".
The House of Lords passed a resolution "That—
(1) No minister of the Crown should give agreement in the Council to any proposal for European Community legislation or for a common strategy, joint action or common position under Title V or a common position, framework decision, decision or convention under Title VI of the Treaty on European Union—
(a) which is still subject to scrutiny (that is, on which the European Union Committee has not completed its scrutiny);
(b) on which the European Union Committee has made a report to the House for debate, but on which the debate has not yet taken place." A similar resolution was passed by the House of Commons.
Lord Willoughby de Broke asked Her Majesty’s Government: "Why they have over-ridden the scrutiny reserve resolution relating to the work of the European Union Select Committee on 157 occasions in the past three years."
Baroness Royall answered for the Government. The full answer can be found at http://www.publications.parliament.uk/pa/ld200607/ldhansrd/text/70515-0001.htm#07051549000007
She explained that "the Government take their commitment to parliamentary scrutiny extremely seriously. Over-rides occur in a small percentage of cases; for example, as a resultof the speed of decision-making in Brussels. The Government are committed to minimising the number of over-rides. In all cases where over-rides prove necessary, Ministers will continue to account for their actions by writing to the chairman of the House of Lords European Union Committee."
In the discussion that followed a number of points were made, including the opinion of one well known Eurosceptic that "the whole system is entirely unsatisfactory? A Minister can go to Europe without any parliamentary approval, make decisions or agree to make decisions, and then come back and say to Parliament, “The decision that I have made, without your prior consent, is binding on you”. Surely, that is not right in a democratic society."
The whole issue of scrutiny of EU affairs was considered by the Commons Modernisation Committee: http://pubs1.tso.parliament.uk/pa/cm200405/cmselect/cmmodern/465/465i.pdf
and the House of Lords EU Committee http://pubs1.tso.parliament.uk/pa/ld200203/ldselect/ldeucom/15/1501.htm