Analysis By Nick Assinder Political correspondent, BBC News

It may be a bit risky for the Tories to throw the word "sleaze" at Labour's frontbench - but that only proves just how serious the dodgy donations affair has become for Gordon Brown.

Harriet Harman is married to the treasurer of the Labour Party Harman: I acted within law

The shadow leader of the house, Theresa May, clearly felt the s-word could now be levelled at Harriet Harman and Gordon Brown without it backfiring and only reviving painful memories of John Major's troubled government, for which Labour spin doctors coined the word sleaze in the 1990s.

And Ms May was determined to get her two penn'orth in, despite several warnings from Speaker Michael Martin to keep within the rules of the Commons questions which, in this case, were supposed to be about the forthcoming Parliamentary business.

She got there in the end.

Ms Harman, the prime minister and the Labour Party's treasurer - who happens to be Ms Harman's husband - were like the three wise monkeys, she offered: "See no evil, hear no evil, speak no evil."

"It will not wash," she predicted. "The public know sleaze when they see it ('they sure do', cried Labour MPs pointing at the Tory benches). People know spin when they hear it."

'Huff and puff'

Ms Harman, who has the prime minister's full confidence - we know that because he has been asked to offer it many, many times and even, on one occasion , given it - was not putting up with that.

She too risked Speaker Martin's ire when she offered her now well-rehearsed explanation that she had only accepted donations from people known to either the party or her deputy leadership campaign team, and who were on the electoral register.

"She can huff and puff but she will not blow this Leader of the House down," she said.

Theresa May branded Labour "sleazy" during the exchanges

Once the wincing and giggling at that little gem had died away, it appeared to dawn on some MPs that Ms Harman had, perhaps, been a touch premature.

Her future remains a matter of great speculation in Westminster, particularly as the dodgy donations affair is far from over and questions remain over why she accepted money from David Abrahams' proxy when others refused.

Thanks to Speaker Martin's scrupulous rulings, however, the clash didn't quite burst into the flames the Tories were desperately attempting to spark inside the Commons chamber itself.

Calls for debate

What has so angered the opposition parties is that Ms Harman has flatly refused to offer a Commons statement on the affair, so they have been denied a setpiece debate in which to attack her and the government over the dodgy donations.

And they are particularly incensed that Ms Harman had decided that she should choose the subject for the afternoon's "topical" debate, and that she had selected apprenticeships as the subject.

For some reason, opposition MPs (and very likely a number of Labour MPs) seem to believe the most topical issue at the moment is political party funding.

Such an apparently outrageous suggestion won little sympathy from Ms Harman, who insisted the plight of all those unemployed individuals crying out for apprenticeships was of far more immediate importance than whether members of the Labour Party had broken the law.

By the end of it all, the Harman house was indeed still standing - but we remain to see whether it is built of straw or bricks.