Donald Macintyre's Sketch: Unsackable minister David Mundell is calm under SNP fire

David Mundell’s speech was certainly long – over an hour – but it probably wasn’t quite fair of his Labour shadow Ian Murray to describe it as “Castroesque”.

For one thing it was lengthened by repeated interventions, including serially from the SNP’s Alex Salmond. Secondly, it’s hard to imagine anyone less like the cigar-chomping father of revolutionary Cuba than the amiable, lawyerly Scottish Secretary.

That said, they had both notched political triumphs against the odds. Indeed, no wonder Mundell seemed so relaxed in his leisurely outline of the Scotland Bill giving Holyrood its promised new tax-raising powers. As the single Scottish Tory MP, he is the only minister who is literally unsackable.

This didn’t stop Nationalist indignation – with both Salmond and the Westminster SNP leader Angus Robertson taunting him with a proclamation by the “Labour-supporting” Daily Record that the Bill did not match the pledges the UK parties had made to secure a Yes vote. The protests were vociferous enough to provoke new Tory MP Heidi Allen – to general nationalist hilarity – into a sweetly innocent call for togetherness. “What I’m hearing is a lack of trust,” Ms Allen, who would be played by Julie Andrews in the movie, declared. There was “nothing we can’t achieve together if we have a little trust”.

Having already tried this commendable approach in a recent NHS debate with zero result, Ms Allen is rapidly emerging as the Pollyanna of the new Parliament. Mundell’s speechathon was helped by his Scottish inflections. The English “Er” sounds hesitant, uncertain. “Eh,” Mundell’s Scottish equivalent – as in “I was just about eh, to go on to the, eh, so-called fiscal framework” sounds somehow measured, statesmanlike. But his task was all the tougher because lots of his own backbenchers would love to scrap the grants to Scotland in the Barnett formula and give the Scots the “full fiscal autonomy” the SNP say they want – but not yet.

If anything Murray was even more effective in challenging the nationalists on their unwillingness to embrace a regime that would have the “severe” cost to Scotland of up to £10bn.

Earlier junior Defence minister Julian Brazier coined the day’s new word. The government, he said, was “upgunning” the role of diplomatic defence attachés world-wide. Unfortunately MPs seemed more concerned about the “downgunning” of the armed forces.