IT'S a non-starter, of course. And Tricia Marwick, Holyrood's Presiding Officer, accepted as much even as she explained her support for a second chamber, fulfilling a similar role to the House of Lords, at the Scottish Parliament.

The difficulties are well understood.

There is the obvious political obstacle, for a start. Could you see voters flocking to the banner of a party that wants to spend millions of pounds creating more politicians?

Then there are the practical problems. How to elect or appoint a second chamber that would not challenge the primacy of the parliament, for instance?

So it's off the agenda, as Ms Marwick acknowledged during an event organised by parliamentary journalists to mark her imminent retirement.

But the fact she was talking about it at all spoke volumes. It underlined powerfully her main message of the evening: the need to reform Holyrood's committee system to ensure that ministers are held to account and that legislation is scrutinised, revised and revisited much more effectively than at present.

It's a long time since the committees were described as the jewel in the crown at Holyrood.

The advent of majority government five years ago gave the SNP a stranglehold over the committees and it turned out the party's MSPs were not afraid to use it.

There have been numerous gripes about the party of government using its majority on the committees to water down reports, block potentially embarrassing inquiries or even put questions to minsters that had been prepared in advance by the same ministers' spin doctors.

The most recent example is probably the worst.

In a report in January, Holyrood's Finance Committee called for the new Scottish Fiscal Commission to be beefed up. It was a sensible, indeed essential recommendation.

MSPs recognised the body should be responsible for producing the tax forecasts on which ministers will base their budgets when new tax powers are devolved.

Under the Scottish Government's plan, it would merely have been required to rubber stamp ministers' own projections.

The potential for mischief was clear. An extra billion here or there can help a finance secretary out of a tricky budget spot, at least temporarily. The experts all agreed they should be spared the temptation and the numbers should be left to an independent, Office for Budget Responsibility-style fiscal commission.

So far so good. But a few weeks later, with John Swinney looking on, SNP MSPs on the Finance Committee voted down their original recommendation.

Alex Bell, Alex Salmond's former policy chief, highlighted this jaw-dropping volte face as one of three key moments when the SNP's "high times turned down forever".

He claimed the party could not tolerate the idea of an independent unit producing economic data that might be unhelpful to the cause of independence.

"Instead of nation-building," he wrote, "the independence party was using its majority to keep Scots in the dark".

I have no idea if that was the reason the Scottish Government favoured a less powerful fiscal watchdog.

But Mr Bell was right to suggest the committee was content to do Mr Swinney's bidding rather than challenge him.

The U-turn came just as the watchdog's role was being discussed as part of the 'fiscal framework' negotiations over Holyrood's new tax powers. MSPs ignored their own recommendation in order to strengthen Mr Swinney's bargaining hand.

"Don't worry," I was told by a member of the committee. "This will all be sorted out at Stage 3."

And it was. During the negotiations, Mr Swinney agreed to beef up the fiscal commission and, with a deal in the bag, the committee reverted to its original position.

The watchdog was finally enshrined in legislation on Thursday and that final, Stage 3 vote was swiftly followed by an SNP press release saying it was great to "reinforce its independence".

On one level, this might look like clever politics.

John Swinney secured a brilliant deal on Holyrood's new powers and, reassuringly, future budgets will be based on independent tax forecasts.

A good result all round. But it is not the role of the Finance Committee to work on behalf of the government.

Ms Marwick steps down in a couple of weeks with a record of reform to be proud of.

She remains frustrated, however, by her failure to shake-up the committees. "Committee reform is not a lost cause, it is a cause that is yet to be won," she said the other night. Her successor should take note.