Perhaps you'll think I'm naïve, but I still believe that when you have a debate, it's a good idea to have some facts readily to hand.
Q.1: Why do they all want to come to the UK? A: They don't. Far more migrants head for Germany and Sweden, which dealt with nearly half of all asylum applications into the EU last year. The ones at Calais are a tiny fraction of the overall number, probably no more than 3,000 out of a total of well over 175,000 who have entered the EU so far this year.
Q.2: So why are the numbers higher than ever? A: They're not -- according to the EU's own figures, there were 672,000 EU asylum applications in 1992 (when there were only 15 members of the EU), compared to 626,000 last year (when the EU had grown to 28 members with a total population of 500 million). It is true, however, that numbers had dropped substantially in the interim. (Click here for the detailed figures.)
Q.3: How many actually apply for asylum in the UK? A: According to the latest government statistics: "There were 25,020 asylum applications in the year ending March 2015, an increase of 5% compared with the previous year (23,803). The number of applications remains low relative to the peak number of applications in 2002 (84,132)."
Q.4: Why aren't the migrants just sent back to where they came from if they're not genuine asylum-seekers? A: Because often we have no way of telling where they came from. Many have no documents, either because they have destroyed them, or because they have been handed over to traffickers who have disappeared.
Q.5: But they can't all be from Syria, can they? A: No, but about a fifth of the total are. The other main known countries of origin are Afghanistan, Kosovo and Eritrea. The biggest increase in asylum applications last year was from Ukrainians.
Q.6: Why don't Syria's neighbours look after Syrian refugees? A: They do. According to the UN, there are more than two million registered refugees in Lebanon, Jordan, Egypt and Iraq, and another 1.7 million in Turkey.
Q.7: If some of the migrants who enter the EU are genuine refugees, why don't they apply for asylum in the first country they get to? A: Huge numbers do exactly that: the number of applications more than doubled last year in both Italy (the main entry point for migrants who have made it across the Mediterranean) and Hungary (entry point for mainly Asian migrants who originally entered the EU from Turkey).
Q.8: So who are the ones in Calais? A: A huge mix of nationalities, most of whom have a particular reason for wanting to get to the UK: they may have relatives or friends who are already here, they may be English-speakers who believe they're more likely to find work here, or they may have heard that there's already a substantial number of others from their home country who have already settled here.
Q.9: Isn' t the real reason that they know they'll get benefits as soon as they make it across the Channel? A: No. According to the independent fact-checking organisation Full Fact, most citizens of non-EU countries who come to live in the UK have no recourse to public funds in the initial years after they arrive, nor are asylum-seekers eligible for welfare benefits while their claims are pending.
Q.10: So why are the media making such a huge fuss about the migrants in Calais? A: Good question. Partly because they're easy to find and easy to get to -- and those long lines of stranded lorries make great TV pictures. So do the desperate images of desperate people risking their lives as they try to leap onto trucks or trains as they head for the Channel Tunnel. And also, of course, because the story feeds into the current debate about the UK's membership of the EU and overall immigration policy. (Plus parliament is on holiday and we're all bored to tears with the Labour leadership contest.)
Do I have the answer to the global migration crisis? No, but here are some suggestions that might help: set up proper, EU-run processing centres at the main entry points: southern Italy, Greece, Hungary. Genuine refugees should be offered asylum according to an agreed quota calculated according to population and GDP. Those deemed non-eligible for asylum would be offered a choice: wait in a camp until your number comes up, and then go where you're sent -- or go home.
The tragedy is that so many people are so desperate that they're prepared to die in an attempt to find a safe place to live. And our response is so blinkered that all we can think of is building higher fences.