I rather like to read articles from the Grauniad even though most are from Metropolitan Liberals, at least they are the antithesis of the idiot Littlejohn. I think this chap is playing devil's advocate as he clearly approves of children brought up in the ultra orthodox Jewish faith to spend the school days learning nothing other than Judaism and being unable to speak the language of their birth when they leave school. He goes on to praise some Muslims for not joining in with society so where does he think extremism comes from?
Retain your culture and identity by all means, but why celebrate the fact that a 20 year old from Hackney is unable to speak English, thus hampering his life chances? People the world over invest lots of time and money to achieve what he could have done with no effort .