This may be a controversial post to some people - I hope not.

[joebloggs]

Thank you for that

I guess many dont bother with the citizenship because it is after all, an unnecessary expense.

in fact there was talk a while ago the gov was going to do something about the large number of people who have ILR, ie get them to apply for citizenship. but some countries like Pakistan dont allow dual nationality. so maybe that's why they didn't do anything.