12/03/2015 09:32 GMT | Updated 11/05/2015 06:59 BST

Worth the Wait: The UK's Aid Commitment Is a Big Step for International Development

Monday marked the end of a long wait. 45 years, to be exact. The International Development Bill passed its third reading - the last step before Royal Assent. The Bill will enshrine in law the UK's commitment to invest 0.7 per cent of our national income (GNI) in international aid. But who is celebrating?

There are some on the political right who say aid is a waste of money and the 0.7% target is arbitrary and unaffordable. Equally, some on the left are unenthusiastic about a focus on aid, seeing it as a 'soft' alternative to what they see as more structural measures. Among the many who have been campaigning on international development in the last couple of decades, few of us were 'switched on' by the aid issue. It was the burden of unpayable debt, the rigged rules of trade, or the call for tax justice that got most of us out on the streets. But we all have cause to celebrate today - for at least three reasons.

First, it is those campaigns that have made this result possible. From Jubilee 2000 to Make Poverty History, campaigners have engaged policymakers and the public alike with a compelling view of how the world could be more decent and more just. And in that world, investing 0.7% of our national income aid is not controversial. It's just something we should do. The fact that opponents of this bill simply could not get anywhere near the votes they needed to stop its passage in either the House of Commons or in the Lords shows the impact of those campaigns in "normalising" a policy like this. And in spite of a determined campaign in parts of the media over the last couple of years, the British public seem stubbornly sane and rational in their support for aid. Yes, they want aid to be even more focused on achieving impact (dedicating at least half of it to the least developed countries would be a great step in that direction). And of course, aid on its own is not going to overcome extreme poverty, preventable disease and gross inequality. Developing countries need to build their own resources and responsible private investment will be required too. Aid alone is not sufficient - but for many countries it will be essential for a long time. The British public recognise this, and in a January poll, two-thirds said the UK should keep its aid promise.

The second cause for celebration is the evidence that campaigning can work and change can happen. It wasn't an accident that the last Labour government committed to reach 0.7%, or that the Conservatives and Liberal Democrats matched that pledge and delivered on it in government. Nor was it pure chance that all three parties made manifesto commitments to put 0.7% into law, which they have now honoured. Even with the major parties' pledges, success wasn't guaranteed. Opponents in Parliament were outnumbered but they were loud and crafty, attempting to use parliamentary procedures to wreck the Bill. But they failed, and the long-time promise to the world's poorest was fulfilled. All these things happened because committed campaigners took the argument to those that needed to be persuaded, marshalled millions of people to support them, and won. In an age of understandable cynicism about politics, that's an exhilarating story.

But the third reason is the simplest. Protecting 0.7% means protecting money for saving and changing lives. Real money. Not enough to make any serious dent in Britain's own budget deficit, but enough to go a very long way in international development. Let's look at the next parliament. If the new government, whoever forms it, were to decide to cut aid from 0.7% down to the 0.56% level it was previously at, about £13 billion would be lost from the aid budget over five years. That amount of money can deliver 2 million anti-malarial bed nets, or vaccinate 1 million children against preventable, deadly diseases such as diphtheria and pneumonia. Without a law to protect 0.7%, these life-lines would be at risk. Because of today, they won't. Instead, the UK will keep investing 70 pence in every £100 of our shared wealth in international aid. It says a lot about the kind of people we are and the country we want to live in. But more than that, it does a lot for the fight against extreme poverty and disease. And now it's going to be the law.