The dramatic intervention took the chairman of the powerful Committee on Standards in Public Life deep into highly charged political territory. He said Parliament had been undermined by the European Union, pressure for devolution, the party whipping system - and Commons sleaze.
Tracking the decline of Westminster from post-war "Imperial Parliament towards offshore regional assembly", Lord Nolan said the contrast between 1946 and 1996 highlighted the "uncertainty about the present-day role and status of Parliament."
The Law Lord said the Commons had shown its readiness to implement changes that could yet restore public confidence in its own standards of conduct.
But he then added: "I think that more needs to be done to restore MPs' own confidence that they have a valuable and meaningful role to perform in contributing to the good government of Britain, and to demonstrate to potential parliamentary candidates, and so to the public, that this is so. I am confident that the House itself recognises this. I hope that it will have the determination to act."
Coincidentally, ministers last night replied to two Commons reports on government - accepting the need for a parliamentary code of conduct for ministers , with heavy qualification; and rejecting calls for more open government.
An official reply to a report from the Commons Public Service Committee said ministers agreed on the need for an all-party resolution of Parliament, "making explicit how it expects ministers to discharge their responsibilities to Parliament."
It then added, however, that the wording suggested by the Committee - ensuring that civil servants should be just as answerable as ministers - was "unacceptable"
The second example of Whitehall's attitude to Parliament came in a response to the call of two Commons committees for more open government: rejecting a Freedom of Information Act and refusing access to original versions of official papers. Derek Foster, the Opposition spokesman on Whitehall, said last night: "Greater access to government information ought to be an entitlement for every citizen. What are they afraid of?"
But Lord Nolan's analysis of the demise of Parliament suggested that the only way that MPs could re-establish their reputation was by standing up for themselves, and fighting their corner against over-mighty ministers and the political machines that dragoon backbench lobby fodder.
In the first of three Radcliffe Lectures delivered at Warwick University, he said: "Parliament is being squeezed from a number of directions. Europe is one. Ministers still have the power of veto over Brussels decisions, except where qualified majority voting has been conceded, but Parliament has not.
"Parliament is also being squeezed from below. One of the consequences of greater stability within western Europe is a reduction in the bonds of necessity which unite the nation state." Nationalism and regionalism was being encouraged by Europe and the direction of funds. "So while as a matter of law, Parliament's ultimate sovereignty remains intact," he said, "its influence has diminished."
Lord Nolan also dealt with the issue which is closer to the remit of his own standards committee - parliamentary sleaze. With investigations at present taking place into allegations about the Conservative MP Neil Hamilton, and an alleged attempt to interfere with an investigation of a select committee into allegations made against him, Lord Nolan warned against any attempt to sweep anything under the carpet.
He said: "The investigation which is now in progress, in what I might call the Hamilton case, is going to be the most difficult conceivable test for the new machinery . . ."