George Osborne delivered a clever, effective speech that may nevertheless have failed to convince undecided voters that they can trust him to guide Britain through the economic turmoil.

The Shadow Chancellor adopted his most sombre tones as he offered the party and the country some “hard truths” and even a “hard path” in the months and years ahead.

True to the extensive pre-briefing, he made reducing debt the guiding theme of both his speech and the first years of a Tory administration.

He also skilfully extended the Conservatives’ responsibility message to the City, warning bankers that they, too, must take a share of the blame for the current global financial crisis and lend a hand in rebuilding a more stable system in the future.

Countering attempts to portray Tories as defenders of privilege, he said that Tories would not “walk on by” while the poorest suffered from the effects of recession.

The passage portraying Mr Brown as the chief croupier in charge of a decade of “casino capitalism” was delivered with deadly accuracy.

But no sooner had he tried on the mantle of prudence he said Mr Brown had abandoned than he gave voters a flash of ankle. His pledge to “freeze your council tax for the next two years” was bound to be compared with last year’s “million pound moment”, when Mr Osborne announced his inheritance tax reforms.

The instant reaction both in the hall and the media was a good deal less positive than in Blackpool. Mr Osborne’s central message is that he intends to protect the poorest while reducing both debt and – over time – the share of national wealth given to public spending. An analysis by the Institute for Fiscal Studies on the effect of the council tax freeze shows that the poorest third of families do not benefit as much as the middle-classes, however.

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