As a UK citizen I'll offer up my two cents...
Immigrants? Yeah, they're fine - because they're legitamately in the country and they're working and putting into the country. The only thing that they're doing is living here. It's not like (unlike BNP supporters and dickheads think) this island is going to sink because there are "Oh so many people on it".
But the intergration into this country is really low level - I mean, people come over here and don't need to learn how to speak English because they will get translators and specialist schools. If they want to go to a very specific denomination of their faith they'll have no real trouble finding a place to worship. They'll be able to find cultural markets and places where they can buy food from their ethnic background's culture and all of that is awesome - good for them!
But...
If you've fled from your country, you are now in England, not in the country you're from. These people have every right to be proud of their heritage, but I sometimes feel (being the child of one 1st gen immigrant, making me "2nd gen", I guess)like these people have every oppourtunity to learn English and socialise with people besides their own ethnic group and get not so much Westernised as more aware of the place in which they live and learn to appreciate it and celebrate our culture (which is theirs if they live here and become a citizen of our country!) as well as theirs.
So many immigrants get a sort of "culture shock", and feel isolated and all that, but by just gaining a little more awareness of the country they're residing in they could understand some of the things they see that needlessly cause them offence and make them do things which in my mind just seem foolish or ignorant.

Tl;dr: Immigrants need more open minds, and so do people who are native to this country.