The chancellor will tell business leaders in Cardiff that he is concerned that there is “a sense we can let up and the good economic news will just keep rolling in”.

This comes fewer than three months after he announced a £27 billion improvement in the public finances in the autumn statement, which allowed him to soften Whitehall spending reductions, cancel tax credit cuts and shield police budgets.

The Office for Budget Responsibility warned yesterday that the £27 billion improvement could easily vanish in months.

The Times reports that Osborne is expected to say that tough times could be around the corner again: “Anyone who thinks it’s mission accomplished with the British economy is making a grave mistake. 2016 is the year we can make the lasting changes Britain so badly needs — or it will be the year we look back at as the beginning of the decline.

“This year the economy is mission critical. Last year was the worst for global growth since the crash and this year opens with a dangerous cocktail of new threats. For Britain, the only antidote to that is confronting complacency and sticking to the course we’ve charted.”

The IMF has estimated that world growth in 2015 was 3.1 per cent, the lowest since 2009. Yesterday the World Bank downgraded its GDP forecasts and warned that “compared to six months ago, risks have increased, particularly those associated with the possibility of a disorderly slowdown in a major emerging economy”.

It cited “falling commodity prices, flagging trade and capital flows, and episodes of financial volatility”. The World Bank cut its growth forecasts for the world economy, which are calculated differently from the IMF, from 3.3 per cent to 2.9 per cent for this year and from 3.2 per cent to 3.1 per cent for 2017. The chancellor will cite the slowdown in China, problems in Brazil and Russia, the risk of stagnation and events in the Middle East as potential hazards.

He will say that strong economic performance such as that seen in the UK is “sadly lacking” in many other parts of the world. “We are only seven days into the new year, and already we’ve had worrying news about stock market falls around the world, the slowdown in China, deep problems in Brazil and in Russia.

“Commodity prices have fallen . Oil, which was over $120 a barrel in 2012, now stands at less than $40.
“That is good for consumers and business customers in Britain, bad news for the oil and gas industry, worrying for the creditors who have lent to it, and a massive problem for the countries that depend on it.”

He also warned that instability in Saudi Arabia, Iran and Syria was causing wider economic problems.