A year after taking office, the prime minister was in big trouble. Inflation and unemployment were soaring. The party was so far behind in the polls that ministers and backbenchers openly speculated about whether the leader could survive until the next general election. The sense of crisis was palpable. But nearly 30 years ago Margaret Thatcher pulled through and became one of Britain’s most successful prime ministers. As Gordon Brown sits ruminating in No 10, he must hope that he can repeat her resurrection.

Mr Brown is no Thatcher, though he has occasionally irked his party by expressing admiration for her achievements. In his honeymoon period as prime minister, a long time ago now, he even stole a march on David Cameron by inviting her to Downing Street. While they are poles apart ideologically, there is a lot he could learn from her if he is not to limp to inevitable electoral defeat in a couple of years’ time.

The first lesson is principle. However much people came to hate Mrs Thatcher when she was in office, few doubted that she stuck to what she believed in. Mr Brown, in contrast, appears to think that if he tells us often enough that he is a man of principle guided by his moral compass we will believe it. We won’t.

Too often in his 12 months in charge Mr Brown has appeared to be driven not by a desire to do what is best or abide by long-held principles, but to drive a political wedge between him and his political opponents. That famous brain is locked into permanent electioneering.

Did he have a principled reason for easing the inheritance tax burden, or was it just to neutral-ise the Tories on the issue ahead of the election that never was? How could a man apparently committed to lifting the low paid up the economic ladder, kick it away from them by abolishing the 10p starting rate of income tax? Was his commitment to 42 days’ detention for terrorist suspects genuinely felt, or just political positioning aimed at presenting the Tories as soft on ter-rorism? The fact the question can be asked underlines how far Mr Brown has to go to establish himself as a prime minister of principle.

One means of achieving that would be to tell the truth rather more often. Mr Brown is not corrupt or attracted to the high life that proved so alluring to his predecessor. But he suffers from a streak of political dishonesty that voters find even more unpalatable than his dourness.

The prime minister was brought up in the old Labour “never concede” school. Any admission of weakness is fatal. So when he decided not to hold an election last autumn, it had nothing to do with a slide in the opinion polls but was purely in the national interest. Nobody would lose out from the abolition of the 10p tax band, he insisted, despite clear evidence from the Treasury that more than 5m families would. In his world black really can mean white.

This kind of behaviour gets politics a bad name and erodes his reputation more quickly than would have seemed possible a year ago. People thought they were getting an honest, unspun prime minister. Now they think they have got a man who doesn’t even know what the truth is.

If, for example, Mr Brown had hinted when he was chancellor that some of Britain’s economic success was due to Tory reforms and favourable global economic conditions, people would accept his explanation now that the downturn has its origins overseas. Instead he tried to give the impression that he inherited a rotten economy in 1997 and single-handedly turned it round.

It is not too late for him to inject some principle and honesty into his leadership. In the past 12 months the gimmicks, hunger for headlines and vacillation have been worse than anything in the Blair era. The best advice for Mr Brown is to do less but do it better. That would be far superior to the relentless, nitpicking interventionism that has characterised his leadership so far. We would all welcome that change.