Ian Katz
Newsnight Editor

It’s become a common refrain in the referendum campaign that voters want more facts and less rhetoric to help make up their minds. But two exchanges in tonight’s show threw into stark relief how even the most basic facts about our EU membership look very different according to which side of the argument they’re viewed from.

The first was about the oft-touted claim by the Leave campaign that the UK sends £350m per week to Brussels. We thought we might avoid argument over it later in the show by running a short film laying out in more detail what we pay to Brussels and what we get back, and seeing if both sides could at least agree on our true membership fee for the European club. 

But leading the Leave side of tonight’s debate, Douglas Carswell stuck doggedly to the line that neither our £5bn/year rebate nor £4bn/year of EU spending in the UK should be taken into account in calculating our EU contribution. The inability of both sides to even agree the cost of EU membership has become a striking indication of how tribal this argument has become.

The two sides saw Britain’s influence in Brussels through equally different lenses. For Remain’s Stephen Wall, the UK was on the winning side of votes 85% of the time, and along with Germany was responsible for initiating most EU legislation. But for Carswell, the more relevant statistic was that the UK had been outvoted on 72 occasions and has just 10% of votes in the European parliament.

In the US, some commentators have been talking about Trump’s rise in the context of a “post fact age”. Once or twice tonight, it felt like British politics may have entered it too.

Why does the European Parliament travel from Brussels to Strasbourg? John Sweeney went to the European Parliament to find out – watch his film here:

Here's another look at a snippet of John Sweeney's European tour.

Sweeney's French teacher and all speakers and appreciators of the French language: close down this page or avert your eyes.

Exactly how many UK laws come from Brussels?

Is it most of the law – or just a bit? It would be lovely to be definitive about this. We asked Queenie, a British bulldog, a national symbol no less, to answer the question. She got the BBC's legal affairs correspondent, Clive Coleman to help. 

In 2015 the EU adopted, external 839 new regulations and 430 amending regulations: a total of 1,269, not 2,500.

However, historically the number of EU regulations was high - In 1983 alone the number exceeded 14,500, external. 

Read more at Reality Check

Since September 2014, EU energy saving measures have banned vacuum cleaners with motors exceeding 1,600W. From 2017 this will drop to 900W.

But is the outrage a whole load of hot air?

Before the deadline many people snapped up high wattage machines. But experts pointed out that suction is more important than power, and that a higher wattage doesn’t necessarily mean it performs any better.

So you can still buy a high performance machine, but it’s worth doing some research to make sure your machine’s suction doesn’t suck.

Not really, as bendy bananas aren’t banned. But the curvature of a banana is regulated.

This isn’t all that crazy; bananas have always been classified by quality and size for international trade. The European Commission drew up rules to standardise banana bendiness laws in EU countries.

But controls are in place. Bananas must be "free from malformation or abnormal curvature". "Extra class" must fully comply, but Class 1 bananas can have "slight defects of shape", and Class 2 bananas can have full-on "defects of shape", as Commission Regulation (EC) 2257/94 so eloquently puts it.

How did Brussels react when they heard that Boris Johnson was comparing the European Union to Nazi Europe? By pure good fortune, the exact moment was caught on camera. 

There's some disagreement between our politicians over how much influence and control the UK has in the EU.

This academic study, external suggests that our panelist Sir Stephen Wall is basically right – we lose votes in the EU about 12 per cent of the time. 

And whether that's inconsequential or a great screaming outrage probably depends on which side of the debate you're on. 

“Brussels” has become the foremost byword for the European Union in its entirety, and “Brussels Bureaucrats” synonymous with Eurosceptic laments of EU excess. But the EU is actually made up of seven institutions split across four cities.

Brussels

Brussels hosts the European Commission, which proposes new laws and the European Council of ministers, which approves or vetoes decisions, and most of the EU’s 23,000 civil servants. It also hosts the European Parliament for three weeks of each month.

Strasbourg

Strasbourg remains the official “home” of the European Parliament, although in reality it only sits for a few days each month – usually for meetings of the full Parliament when votes take place.

Luxembourg City

The European Court of Justice, which ensures EU law is applied equally in all member states, is based in Luxembourg – the second smallest country in the Union. Despite being home to just 0.11 per cent of the EU population, Luxembourg also hosts a 4,000-strong Secretariat and the Court of Auditors.

Frankfurt

The European Central Bank oversees EU monetary policy and the Euro. It opened in Frankfurt in 2008 – a decision which prompted France to demand the first president be French. He wasn’t, but they got the second – Jean-Claude Trichet – who served from 2003 to 2011.

How many of our undecided voters support spending British taxpayers money on the development of poorer central and eastern European countries? Well, all of them. Perhaps surprisingly.

Douglas Carswell isn't convinced – he tell us that money might not even be available if the Union continues to expand and admits countries like Turkey.

And speaking of Turkey, there's a BBC Reality Check on that here. 

Here's John Sweeney sitting on one of those boxes used to move the entire European Parliament from Brussels to Strasbourg for a week. Our hearts go out to the man pushing that box for 300 miles... 

For one week every month, the entire European Parliament abandons Brussels in Belgium and moves wholesale to Strasbourg in France.

More than 2,000 plastic trunks are loaded on to lorries and sent 270 miles southeast, while officials, translators and MEPs make the same expedition on specially-chartered trains.

Critics put the annual bill for this Strasbourg shuffle at about £100 million

The process has continued since the nascent days of the Union despite widespread criticism even within the Parliament itself.

Why? Well, the simple answer is that France doesn’t want to give up its stake.

Abolishing the French wing of the parliament would require treaty change – that means all 28 states have to agree to it, and France won’t.

Strasbourg was originally chosen partially for symbolic reasons – it borders Germany and thus represents the overcoming of adversity between the two nations.

Splitting the locations originally meant sharing the burden of creating - and the rewards of hosting – an entirely new parliament. It was, the founding fathers noted, a compromise.

Responding to a plan hatched by some commissioners in 2013 to end the monthly pilgrimage, France’s Europe Minister said: “The decision is sacrosanct and non-negotiable.”

Compromise indeed.