Click any step to jump to it - the lit step is the one showing below. Deepening integration, then the vote to reverse it. Green = strengthened or expanded · Amber = mixed or contested · Red = weakened or curbed.
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What happened. The UK joined the European Economic Community on 1 January 1973 under Edward Heath, the European Communities Act 1972 bringing EU law into UK law.
What it shows. Pooled sovereignty begins - some decisions now made collectively at European level. Joining
What happened. Harold Wilson's government held a referendum on staying in; about 67% voted Yes, and collective responsibility was suspended so ministers could campaign on both sides.
What it shows. Membership confirmed by the public - but the European question was already divisive. First referendum
What happened. The Single European Act 1986, signed under Margaret Thatcher, drove the single market programme toward its 1992 deadline and extended qualified majority voting.
What it shows. Deeper economic integration - more decisions taken by majority rather than UK veto. Single market
What happened. In the Factortame case, the European Court of Justice and the House of Lords held that EU law took priority, and the Merchant Shipping Act 1988 was disapplied where it conflicted.
What it shows. Pooled sovereignty as concrete fact - an Act of Parliament effectively overridden. Pooling proven
What happened. The Maastricht Treaty, signed under John Major, created the European Union (1993) and widened competence beyond trade; the UK secured opt-outs from the single currency and the Social Chapter.
What it shows. The EU's reach widened, though UK opt-outs retained some powers. Maastricht
What happened. The EU's eastward enlargement brought in Poland and others; the UK did not impose transitional controls, and free movement drove substantial migration.
What it shows. Free movement of people now had a large practical effect - a central later Brexit argument. Enlargement
What happened. The Lisbon Treaty, signed in 2007 and in force in 2009 under Gordon Brown, deepened integration with more qualified majority voting and a stronger European Parliament.
What it shows. The UK could be outvoted even in intergovernmental bodies - the sovereignty complaint sharpens. Deepest integration
What happened. David Cameron renegotiated terms in 2015-16 and held the referendum on 23 June 2016: 52% Leave on a 72% turnout. He resigned the next day.
What it shows. The country voted to reverse pooled sovereignty - the road out begins. The vote to leave
Roll up and down: use the arrows, scroll or swipe inside the box, the up and down keys, or click any step in the arc above.
The road in begins with the European Communities Act 1972 and accession in 1973 under Heath, confirmed by the public in Wilson's 1975 referendum. From the start membership meant pooling sovereignty - some decisions taken collectively at European level rather than purely at Westminster.
Integration then deepened. The Single European Act 1986 built the single market under Thatcher; Maastricht 1992 created the EU under Major, with UK opt-outs; the Lisbon Treaty 2007-09 extended qualified majority voting. Factortame (1990) proved the constitutional reality - an Act of Parliament could be disapplied where it breached EU law.
The 2004 enlargement made free movement a large practical issue, and that, with the sovereignty argument, fed the politics that led to Cameron's 2016 referendum and the vote to leave - the point at which this story hands over to the Brexit timeline.
The same events split by side. Build each paragraph around one point from each column, then judge.
Factortame is the strongest "erosion" point, but the "recovery" argument notes that in strict legal terms Parliament never stopped being sovereign - which is why Brexit could undo it.
For "Evaluate the view that EU membership eroded UK parliamentary sovereignty", this timeline gives both sides. The ECA, Factortame, Maastricht and Lisbon argue sovereignty was pooled and constrained; the opt-outs, the UK's seat at the table and the reversibility shown by Brexit argue the constraint was limited. End each paragraph with an interim judgement.
Keep the milestones precise: ECA 1972 and accession 1973, the 1975 referendum, the Single European Act 1986, Factortame 1990, Maastricht 1992, the 2004 enlargement, the Lisbon Treaty 2007-09, the 2016 referendum.