Iain Duncan Smith is a former Secretary of State for Work and Pensions, founded the Centre for Social Justice, and is MP for Chingford and Woodford Green.

Today in the House of Commons we see the first step delivering on the historic vote on 23rd June 2016, in which a majority of the British people voted to leave the European Union. This very short Bill – four lines long – will give the Government the power to trigger Article 50. Doing so will start the clock ticking on a process that will last for up to two years after which the United Kingdom will, after some 40 years, throw off its membership of the EU.

Yet as we come to vote, it is worth reflecting on what this is not about, as much as what it is about. The triggering of Article 50 is not, as some maintain, the detail of the negotiation; it is simply a legal device which both starts the two-year process and enables the EU and the UK to engage in negotiations. In effect it is what is required to start the process of delivering on the British people’s vote to leave. The full detail of how that will be accomplished is yet to follow with the repeal of the 1972 European Communities Act. That process of repeal will cover every dot and comma of our relationship and I am sure will subsume Parliament in vexed debate lasting many months. As if that were not enough, all that debate will then be followed by a vote on the final outcome of the EU/UK negotiations.

For example, I was fascinated to hear so many – particularly Scottish Nationalists – running around on every news outlet they could find, threatening to swamp this narrow Bill with amendments. Their purpose, as they have so often made clear, is transparently to delay the passage of the Bill. However, I am sure some others sincerely seek to tie the Government’s hands by laying amendments, yet many strangely seem to do so on things the Government is already doing. One amendment demands that the Government return to the House regularly to update the Commons, as though such action would somehow be a revelation. In fact, in case they hadn’t noticed, David Davis, Boris Johnson and the Prime Minister have been at the despatch box again and again and will continue to be until we finally leave.

Yet, despite all the debates in the last year, for me personally the triggering of Article 50 brings to an end a long chapter which started as I arrived as a new MP in 1992 with the passage of the Maastricht treaty. I recall some 25 years ago how having just arrived in Parliament I and others were faced with a difficult decision as to whether or not to support the passage of that Bill. I chose to oppose it because following the Single European Act I believed it fundamentally changed the nature of our relationship with what had been the EEC and became the EU. The vision of Altiero Spinelli, the chief architect of both ground-breaking treaties, of a Europe in which the nation state was subsumed into a federal union was set in train and would, I believed, in time lead inevitably to the UK’s departure.

As I reflect on those Maastricht debates, I am also conscious how the political landscape has turned around in recent months. From Margaret Thatcher’s demise onwards, for many years the struggle that came to characterise British politics was the Conservative Party’s internal war on the European Union. Yet now, as the vote approaches, it is Labour which is in disarray, rent by the Europe issue, with shadow ministers resigning and many Labour MP’s set to defy the whip. For my party, the heat seems to be dissipating. Nicky Morgan’s article on this site yesterday illustrated this when she made it clear that most of those like her, who were very strongly opposed to our departure, will, despite their misgivings, vote to let the Government trigger Article 50.

We are leaving and as we start the official process we should recognise that away from Westminster and some of the heated debates, people are getting on with their lives. In line with that, I have been intrigued by four recent signs that the dire warnings from the campaign have been ignored by the public and now left behind us.

The first is that AstraZeneca has committed to a $500 million headquarters and research centre in Cambridge, while GlaxoSmithKline pledged $360 million to expand manufacturing in Britain in July, just five weeks after the Brexit vote. Novo Nordisk, the world’s top maker of diabetes drugs, is investing £115 million ($145 million) in a new research centre in Britain.

Second, in a British Chambers of Commerce survey of 1,500 business people, nearly a third (31 per cent) said they are looking to export more following the EU referendum, and the majority of respondents (65 per cent) said the EU referendum hasn’t changed their strategy for importing.

Third, Barclay’s chief executive said recently that he believed that after the UK leaves the EU, Europe’s financial centre will continue to be the city of London, as did the head of Frankfurt’s financial services.

Fourth – and perhaps most surprising – is the news that there has been a surge in optimism among young people about jobs. Deloitte’s quarterly consumer tracker showing confidence among the 18-34 age group rose to its highest level since the advisory firm started its tracker.

There is a long way to go yet and many arguments to be had but perhaps now is a time to reflect that although we cannot see the future we do have how we have reacted to change in the past as our guide. That is why I remain optimistic, for I have always believed that the UK is capable of rising to any challenge thrown at it. As we begin the process of leaving, I believe the people of this great Union will rise to the challenge once again.