Good man, John Bercow. The Speaker of the House of Commons is what management gurus call disruptive; it means sound. Just six weeks from an election, he said on Tuesday that MPs needed £3bn from the taxpayer to tart up their offices and rid them of mice. The press reacted as if he were offering massage parlours to prisoners. How dare he pander to those pampered MPs? Besides, when anyone in parliament says £3bn it means £6bn and rising.

Bercow added that so bad was the condition of the Palace of Westminster – surely the world’s greatest neogothic building – that parliament might have to move out for the duration of repairs. “I will tell you in all candour,” he said ominously, “that unless … a not inconsequential sum of public money is deployed on this estate over the next 10 years” its continued use as a parliament would be impossible. He added that temporarily decamping elsewhere should be considered, “including almost certainly a regional option”. But he was uneasy, “since once you are out it can be very difficult to get back”.

I sense a Cromwellian moment. Was ever the Commons less popular? Dodgy expenses, infantile question times, committees packed with lobbyists, cash for access, cash for peerages, cash for everything, and now MPs want £3bn for a nicer palace. As the Lord Protector cried (on 30 April 1653): “Ye sordid prostitutes, ye are grown intolerably odious to the whole nation. The Lord hath done with you. Go, get out, make haste, ye venal slaves, be gone.”

Go indeed, but on what terms might they return? Bercow’s suggestion of a regional location is admirable. Birmingham might bid for Kenilworth, venue of Simon de Montfort’s first Commons, but it would need a huge marquee. Meanwhile the Cromwell of our day, George Osborne, has established Manchester as second city in the land. It is well appointed, with a good airport and two hours by train from London. MPs could fit easily into Manchester’s town hall, its vast chambers, corridors and committee rooms almost a facsimile of Westminster. As for the lords, they could meet in Liverpool’s St George’s Hall.

There would be nothing like this to so acknowledge the revival of provincial England. Nothing would do more to correct the metropolitan centralism of modern government. A regional move would reassert parliament as a popular congress of a united kingdom. It would be a gathering of the commons, not a colloquium of elites. Removal from London would weaken parliament, but that in turn might encourage it to self-assertion.

After five years’ absence, parliament might vote not to return. Manchester could be to London what Canberra is to Sydney, or Brasilia to Rio de Janeiro. I agree with Bercow that this would be a pity. The Palace of Westminster may not be fit for purpose, but it is a holy of democratic holies. Venal it may be, but it symbolises British history as does no other building, not even Buckingham Palace or Westminster Abbey.

Assuming the MPs would want to return, it is a heaven-sent opportunity to cut a deal for their £3bn. Play ball, parliament, we should say, or Westminster goes to Holiday Inns.

The recent fly-on-the-wall documentary Inside the Commons made good watching, but the content displayed the BBC’s customary reverence. The sense was of a down-at-heel public school, the warts all non-malignant. Arcane customs and procedures baffled new MPs, until they were slowly drawn into the freemasonry. With parliament mostly an electoral college of candidates for government, there was no purchase in nonconformity. The only spark of life was from an occasional select committee.

I have uncommon sympathy with MPs. They are underpaid and their working conditions are awful. They must share offices, stay late, vote in person and lead broken family lives, for no cause beyond that of ceremony and tradition. It is a wonder more are not as corrupt as some are. The documentary showed how the government systematically precludes MPs from scrutinising its work. We can see why the US Congress is a more effective body.

If MPs do go to Manchester and wish to return, they should clean up their act. A “commission of the people” should lay down terms and conditions for the reoccupancy of Westminster. There should be 400 MPs, not 650. They should sit at desks, as in every other world assembly, and meet in plenary in Westminster Hall or the atrium of Portcullis House. Their predominant work ought to be on properly resourced committees.

MPs should be paid six-figure salaries, with no outside “interests”, and the number of ministers should be capped by statute. The idea that this would deprive parliament of “good people” is rubbish. These days, outside interest means corrupt opportunity. At present the press does parliament’s job for it, with a daily barrage of scrutiny. While this may fill me with pride, it is not how democracy should operate.

Parliament has often been in bad public odour, but its unfitness for purpose today is glaring. Yes, the bear-pit atmosphere of the Commons is more fun than the sombre exchanges of a Scottish or Welsh assembly, but it is not good oversight. The age of coalitions is at hand, and with it the need to systematise the cross-cutting deals and pressures of party politics. Scrutiny of ministers has never been more necessary. An occasional howl of anguish from the accounts committee’s Margaret Hodge is not enough.

As for the lords, their days are surely numbered. With 800 members and rising, Britain has the only parliament in the world whose membership is shamelessly, worthlessly sold by parties to tycoons. No British minister can uncritically accuse a foreign state of corruption. Second chambers are useful to debate and monitor legislation, but that can be done by 200 worthy terriers on fixed-term appointments detached from political parties. Titles can go elsewhere.

Bercow says a new Westminster should ensure “that we are a parliament fit for purpose, and that this Victorian legacy can be rendered practical for contemporary representation”. The ceremonies of state are fine for Charles Barry’s masterpiece. But parliament should become a modern estate of the realm, standing effective against the executive, not its poodle. Fitness for purpose should not accompany Westminster’s repair – it should be its unbreakable requirement.