This year sees the anniversary of two key moments in European history involving Conservative prime ministers. In 1957, the Treaty of Rome was signed without Britain’s name on it. As a result, when Britain did join Europe 15-years later, we had to follow rules set by others.

It was a mistake Britain would never make again. That is until the present leadership of the Conservatives under David Cameron, who seems to want to collapse into a big, UKIP, anti-EU swamp. He has made clear through his deeply Euro-sceptic deputy leader, William Hague, that a Tory-led Britain would say ‘no, never, no-way’ to any new steps in European construction.

This February, however, sees the 15th anniversary of the Maastricht Treaty. It began under Margaret Thatcher’s premiership and was ratified in the Commons under John Major’s leadership. Although today’s Tories like to deny the fact, history shows that Thatcherism in its full glory days was committed to the biggest sharing of sovereignty with other European nations that Britain has ever seen.

The economic foundations were laid by the Single European Act. But to break down the 1001 national protections that stopped the act from working – and which are still used by countries to deny British academics, firms and workers fully free rights to work and trade – it was quickly realised that Britain had to share power with its partners. It was this that prompted the move to majority voting in a number of areas. Today, as a result, 2.2 million Britons live and work in other EU countries with full citizenship rights, including the right to elect a Briton as a mayor in Spain or France.

The Maastricht Treaty was also a first response to the huge political, economic and social upheaval that came after the end of the historical epoch of the cold war. The treaty extended the power of the European parliament and extended qualified majority voting in extra areas. It created economic and monetary union, to be completed before the end of the decade, and thus opened the way to the Euro, a currency which today is stronger, more stable and, in terms of notes in circulation, bigger than the US dollar.

Maastricht also underlined that social and civil rights had to be part of a successful Europe. Today, British workers enjoy five statutory paid weeks of holiday a year. This is not generosity by a Labour government but a direct result of Maastricht’s social protocol. In the 15 years since Maastricht, Europe’s political profile has changed dramatically. The number of member states has gone from 12 to 27. Europe has become a world actor, with its soldiers operating from the shores of Lebanon to the frontiers of Pakistan.

Despite the No votes in France and the Netherlands, 18 member states have ratified the recent, much-maligned constitution, which they see as no more dramatic than the Maastricht Treaty or the Single European Act. Over here, it is easy to sneer at the poor, benighted Europeans who want to move ahead. But if progressives believe we need to work within Europe to tackle global warming, trans-border crime and terrorism, as well as craft intelligent policy on the Middle East, then a go-it-alone, gung-ho Britain will be isolated and unable to help shape EU decisions.

Today, the question of political, social, and economic Europe is back on the agenda. Can a new Labour government find a new confidence on Europe, or is Britain’s fate always to respond to proposals made by others? There was a gloating – almost triumphalist – relief in many parts of government when Labour was spared the question of the EU constitution by the No votes in France and the Netherlands. This comfort zone period is now coming to an end. On the 50th anniversary of the Treaty of Rome and the 15th anniversary of Maastricht, Labour needs a new script and a new enthusiasm on Europe, or soon it will be the Tories calling the shots.