One can never predict exactly how a Government is going to go down in history. Perhaps this will be the administration that oversaw the break-up of the UK, or which joined a Western de facto appeasement movement, tacitly encouraging Vladimir Putin to invade the Baltic states in 2021 – who knows?

One of the few labels you can be sure will be attached to the Coalition in the history books will be the word “austerity”. The debate over whether reducing the increase in spending is really austere (or austere enough) will no doubt continue for many years, but the general drive to reduce the deficit is inherent to the Cameron/Osborne/Clegg mission.

International aid spending is, therefore, a historic anomaly. While the NHS is ringfenced, DFID’s is the only budget which the Government expressly intends to drastically increase.

In a neat demonstration that it’s always easier to spend taxpayers’ money than it is to save it, the department has easily hit the target of spending 0.7 per cent of GDP on aid. We’re the first country in the world to do so, following a staggering increase of 28 per cent last year alone, from £8.3 billion to £10.6 billion.

That’s a large sum – more than our net contribution to the EU, for example – and a huge increase. Put in its international context, this rise makes Britain the second biggest donor after the US in cash terms.

Defenders of aid spending all too often dismiss taxpayers’ concerns with a big state wave of the hand: oh, it might look like a lot to you, with your little house and your package holiday, but it’s actually tiny when you consider the state spends £700 billion a year. That’s true, but hardly comforting – we ought to be alarmed, not reassured, about a system so addicted to tax and debt that £10.6 billion is a mere drop in the ocean.

As I wrote in September, the electorate’s attitude to aid spending is complex and considerate, contrary to unfair stereotypes of ignorance and selfishness. People support the idea of helping others in crisis – which is one reason why the British public are often extremely generous with voluntary donations following an earthquake, tsunami or civil war.

What taxpayers are not, however, is stupid. They are more savvy – and hawkish – than the aid establishment when it comes to assessing the performance of spending. We’ve all heard the arguments in favour of increasing the budget, now we want to see them bear fruit.

If aid is about development, rather than simply handing out food to stave off immediate crisis, it’s reasonable to expect to see the budget fall over time.

If aid is about living up to our responsibilities as a global nation, and standing by our friends, we should see a growth in our influence around the world to match the growth in our spending.

If aid is about promoting prosperity and peace abroad, then we should see resources shift from corrupt or authoritarian nations which oppress their people or attack their neighbours to those who are willing to reform politically and socially.

In short, the Government should pay rather more attention to justifying this budget increase to the people paying for it, and rather less to self-congratulation. Taxpayers need to know what bang they are getting for their buck: where are the new allies won by our provision of help? Where is the plan to reduce aid spending as poorer nations develop thanks to our funding? Where are the countries ditching anti-gay, anti-Christian or other oppressive laws for fear of losing British aid?

Unless those questions are answered, the sudden bulge in the budget for one department may go down in history as a very odd decision indeed.