FMQs sketch: Nicola eases her pain by finishing off a Rennie

With his gap-toothed grin and Dumb and Dumber haircut, the leader of the Scottish Liberal Democrats was practically born to take a kicking.

After a sticky first half at First Minister's Questions, Nicola Sturgeon's joy at the appearance of this walking open goal was palpable.

She wasted no time hoofing him in the guts.

Prior to that zenith, the FM had been toiling over Scotland's finances.

Labour's Kezia Dugdale asked whether the SNP's plan for Full Fiscal Autonomy meant scrapping the Barnett Formula.

Ms Sturgeon was instantly crabbit.

No, it was more than that.

It was beyond crabbit, it was Crabbit Max.

It was as if, poisonously hungover, she'd got out the wrong side of bed, tripped, stubbed her toes on the way to the kitchen, then discovered only after a mighty swig that the milk was sour.

"So much for the new style patriotic Scottish Labour Party," she growled.

"It did not really last long, did it? Labour has grabbed the first opportunity to get right back on to the same side as the Tories, to gleefully tell Scotland how useless it thinks we are."

Undeterred by the random spleen, Dugdale pulled a good gag from her sleeve.

"Last year, the FM said scrapping Barnett would cost Scotland £4bn. Yesterday, Scotland's official accounts confirmed that she was absolutely right. Does Nicola Sturgeon still agree with herself that scrapping Barnett would have cost Scotland £4bn last year?"

The best the FM could do was complain the Tories liked the joke.

Actually, everyone liked the joke.

The pair then tussled over jobs, with Ms Dugdale roadtesting the phrase "Barnett Bombshell" for the coming election, and claiming the SNP's plan would cost 138,000 Scottish pay-packets.

"If anybody is wondering why Labour is in the dire straits that it is, they only have to listen to Kezia Dugdale today," griped Ms Sturgeon.

Tory Ruth Davidson asked the FM to name the year in which the UK deficit would disappear under the SNP's plan for higher spending and more borrowing.

Ms Sturgeon admitted she wanted a "slower" debt and deficit reduction than the Tories, but specific answer came there none.

"It is clear that the SNP has not a clue," snorted Ms Davidson.

The FM said there was a clear choice before voters.

"We can accept never-ending Westminster cuts from the Tories, the Liberals and Labour, or we can take more control of our own finances and build a better future for this country."

But against a backdrop of hulking deficit projections, all the talk of a new tomorrow made it sound like Ms Sturgeon's Scotland would be built from rainbows and lollipops.

Then, like a soothing balm to her furrowed brow, came Mr Rennie.

His error, on the day his LibDem colleague Danny Alexander was all over the headlines for donation trouble, was to mention money.

With its implications for more debt and its dodgy oil forecasts, the FM's economic plan was falling apart, he claimed.

Mr Sturgeon's smile glinted like an executioner's blade.

"I would thought that money might be the last subject that the Liberal Democrats wanted to talk about today," she replied.

"We have had an interesting insight into how they deal with the indebtedness of their own party."

But Mr Rennie's naive hope of getting the better of her was undimmed.

"The First Minister needs to come clean," he declared, again forgetting Mr Alexander's woes.

As the SNP benches collapsed in ironic laughter, John Swinney slapped his knee so hard you feared the reflex would send his desk into orbit.

"Order! Order! Let us hear Mr Rennie," interjected Presiding Officer Tricia Marwick.

For a full ten seconds, there was an uneasy calm.

Then, as only the truly guileless can, Oor Willie defended the Coalition.

"The UK economic record is sound," he beamed, with a goofy thumbs up gesture.

"Rubbish!" came back the gentlest of a dozen catcalls.

Somehow he squeezed in a final point about the SNP's higher spending meaning £4.7bn more in debt interest, or 180 secondary schools a year denied, but it mattered not a jot.

"There is certainly somebody who needs to come clean today in politics," said Ms Sturgeon.

"But it is nobody on the SNP benches."

The LibDems were helping the Tories advance policies that penalize the poor, she went on.

"If that is what the Liberal Democrats stand for, it is no wonder people cannot wait to give them a complete doing at the ballot box on 7 May."

Punchdrunk and oblivious, Mr Rennie grinned merrily on.