Anne
I have watched news crews filming some of these people who claim not to understand English when they have come out of court laughing and joking in English.
Also foreign Nationals who have entered this country legally can be deported as can people who have not taken British citizenship and have retained their own Nationality. This is in fact done sometimes, but not often enough in my view.
I don't know if you realise but we have gangs of pickpockets, ATM riggers, and other thieves come to this country solely to commit crimes. Why should this country give them any thought at all, why should they cost taxpayers one penny. They would get the due process of the end of a boot as they left the country if I had my way.
Phil