This was billed as TELC Signature Event – Can a language test measure integration. The discussion is interesting with loads of great quotes. I do recommend you watching it. One of the lines I liked most was by someone called Horatio Clare who abhors the notion of borders, at 25:31 mark he says:
A lot of Brits don’t eat Turkey on Christmas day, most Brits can’t tell you when women got the vote. Knowing these things doesn’t tell you that most women in Britain don’t vote and that the government was elected with 24 percent of the electorate. These things are the real Britain to which they are coming to.
All the participants recognised the deep political aspects of this issue that is beyond any simple debate on test validity.