Here is a quiz question: what was the last notable vote that Margaret Thatcher cast in the House of Commons? It was asked by Andrew Adonis, the Labour peer and anti-Brexit campaigner, when he came to give a talk at King’s College, London, recently.

We had to admit we did not know, so he told us: “She led a rebellion of 20 Conservative MPs in February 1992 in favour of a referendum on the Maastricht Treaty.”

This is surprising because Thatcher was known as an opponent of referendums. As the new leader of the opposition in 1975, she argued against the principle of the referendum when it was introduced into UK politics by Harold Wilson. Indeed, she went so far as to refuse to commit the Conservatives to abide by the result – although she did campaign enthusiastically to stay in the European Economic Community in that referendum.

So it was a grand irony that the lady who was “not for turning” supported a referendum on the treaty that paved the way for the single European currency.

As prime minister, she had started to shift her position just before she left office. After Michael Heseltine launched his leadership challenge, she told The Sunday Telegraph on 18 November 1990: “I would not rule out a referendum [on economic and monetary union]. I think you should hold them only on constitutional issues because otherwise you cannot separate out a particular issue in an election.”

The reason Adonis brought this up was that he thinks referendums are a bad idea. He blamed Thatcher not just for anti-EU sentiment but for pushing the idea of a referendum as a way of advancing it.

And, despite being one of Tony Blair’s most important advisers and ministers, he also blamed Blair for giving credibility to referendums. (This was the point of his talk: an assessment of New Labour’s record for a course I co-teach at the university called “The Blair Years”.) Before the 1997 election, Blair copied John Major’s promise of a referendum on the single currency, and later promised one on the EU Constitution, neither of which were needed. He promised but never held a referendum on a proportional voting system. He also promised and held referendums on devolution to Scotland, Wales, London, Northern Ireland and directly elected mayors.

“This whole headlong rush to referendums was significantly advanced by Tony,” said Adonis. And that ended in what he called the “massive self-inflicted wound” of the 2016 vote to leave the EU. Adonis cannot be accused of opposing referendums in principle simply because he didn’t agree with that result, because he was against a referendum before it was held (as was Ed Miliband as Labour leader – and he was one of only 22 Labour MPs who refused to vote for the bill in June 2015). Although it could be that Adonis feared the result would go the “wrong” way. And I do think he dismisses too easily the case for direct democracy on fundamental constitutional questions.

He was on less secure ground in his argument against electoral reform. I wrote earlier this week that he had changed his mind about proportional representation. He told the students that he now thinks the proportional system for European Parliament elections in 1999 was a “huge mistake”.

This was surprising from someone who is a great admirer (and one-time official biographer) of Roy Jenkins, the former leader of the Social Democratic Party who was drafted in by Blair to devise a new voting system for the House of Commons.

What was less surprising, perhaps, was the reason for Adonis’s change of heart: it was Brexit again. Working back from the “calamity” of the referendum vote, he said: “Ukip came in as a serious political force because of the proportional system for European elections. If we had kept first-past-the-post, there would have been no Nigel Farage.”

The biggest issues facing UK on leaving EU Show all 8 1 /8 The biggest issues facing UK on leaving EU The biggest issues facing UK on leaving EU Post-Brexit immigration workers sorting radishes on a production line at a farm in Norfolk. One possible post-Brexit immigration scheme could struggle to channel workers towards less attractive roles - while another may heighten the risk of labour exploitation, a new report warns. PA The biggest issues facing UK on leaving EU Customs union A key point in the negotiations remains Britain's access to, or withdrawal from, the EU customs union. Since the referendum there has been hot debate over the meaning of Brexit: would it entail a full withdrawal from the existing agreement, known as hard Brexit, or the soft version in which we would remain part of a common customs area for most goods, as Turkey does? No 10 has so far insisted that “Brexit means Brexit” and that Britain will be leaving the customs union, but may be inclined to change its position once the potential risks to the UK’s economic outlook become clearer. Alamy The biggest issues facing UK on leaving EU Northern Ireland-Irish border Though progress was made last year, there has still been no solid agreement on whether there should be a hard border between Northern Ireland and the Republic of Ireland. To ensure borderless travel on the island, the countries must be in regulatory alignment and therefore adhere to the same rules as the customs union. In December, the Conservative Party’s coalition partners, the DUP, refused a draft agreement that would place the UK/EU border in the Irish Sea due to its potential to undermine the union. May has promised that would not be the case and has suggested that a “specific solution” would need to be found. Getty The biggest issues facing UK on leaving EU Transition period Despite protests from a small number of Conservative MPs, the Government and the EU are largely in agreement that a transitional period is needed after Brexit. The talks, however, have reached an impasse. Though May has agreed that the UK will continue to contribute to the EU budget until 2021, the PM wants to be able to select which laws made during this time the UK will have to adhere to. Chief negotiator Michel Barnier has said the UK must adopt all of the laws passed during the transition, without any input from British ministers or MEPs. EPA The biggest issues facing UK on leaving EU Rights of EU citizens living the UK The Prime Minister has promised EU citizens already living in the UK the right to live and work here after Brexit, but the rights of those who arrive after Brexit day remains unclear. May insists that those who arrive during the transition period should not be allowed to stay, whereas the EU believe the cut-off point should be later. Getty The biggest issues facing UK on leaving EU Future trade agreement (with the EU) Despite this being a key issue in negotiations, the Government has yet to lay out exactly what it wants from a trade deal with the EU. Infighting within the Cabinet has prevented a solid position from being reached, with some MPs content that "no deal is better than a bad deal" while others rally behind single market access. The EU has already confirmed that access to the single market would be impossible without the UK remaining in the customs union. Getty The biggest issues facing UK on leaving EU Future trade agreements (internationally) The Government has already begun trying to woo foreign leaders into prospective trade agreements, with various high profile state visits to China, India and Canada for May, and the now infamous invitation to US President Donald Trump to visit London. However the UK cannot make trade agreements with another country while it is still a member of the EU, and the potential loss of trade with the world's major powers is a source of anxiety for the PM. The EU has said the UK cannot secure trade deals during the transition period. EPA The biggest issues facing UK on leaving EU Financial services Banks in the UK will be hit hard regardless of the Brexit outcome. The EU has refused to give British banks passporting rights to trade within the EU, dashing hopes of a special City deal. However according to new reports Germany has suggested allowing trade on the condition that the UK continues paying into the EU budget even after the transition period. Getty

That sounds like a bad argument against electoral reform to me. Voting systems should not be judged by whether a single vote goes the “wrong” way.

My view is that Farage and Ukip made themselves felt in the first-past-the-post system of UK politics. David Cameron felt under pressure from them because they threatened to take votes away from Conservative candidates in local and general elections. The money and the platform of seats in the Brussels parliament were incidental.

And the reason that Ukip was a threat to the established parties is that it represented a large number of people who wanted to leave the EU. That sentiment was not created by Farage; it created him. Public opinion forced a political system run by Remainers to give it a direct say on the country’s future.