Look at the stats which Brian's provided, Ted - invasion? I'm afraid the problem is still that people WILL confuse the different types of incomers: economic migrants, immigrants, and asylum seekers. The latter's dropped a lot now to the UK, as parts of the world have either calmed down or been put under some sort of restraint. That tens of thousands of Iraqis are fleeing to Jordan doesn't concern the UK figures.
Within the category of economic migrant, you have people coming here to work, usually for a specific purpose or time. They're often seasonal workers who come to work in the catering/seaside/agricultural areas and depart home when they're work is done. Just the same as the thousands of British who depart to do exactly the same thing out of the UK - you mightn't realise that a huge amount of Dutch tulip-picking is done by fair English hands, yet the Dutch haven't yet lynched any of us for doing so, nor the French for helping out in the lavender fields, or any of the other countries which welcome people from these shores to work.
You also have workers from other Eastern Europe coming here for one, two, maybe a few years to work in usually crap jobs (street cleaning, litter-picking, 'facilities' cleaners, etc.) because even doing those jobs they earn four times more than they do with their University qualifications back home in Poland or the Ukraine. When they've amassed the money they want (and paid taxes on it, too) they may well return home to start up businesses and keep themselves and their families in much better conditions than could be managed on national rates of pay. A young Polish man aged 22, working in our local convenience store (and with excellent English language skills) earns just £4.65 an hour, not a job many of us on this forum would covet, I imagine, but twice what he could earn at home. He plans to spend 'a few years' here with his fiancee, also earning similarly, and then they can return to Poland, buy a very nice house, and be financially secure to either buy their own business or further their educations. You have any problems with that?
Immigration - that is, people who are admitted to reside permanently in the UK, are different. They'll be owning homes or businesses (and generating jobs in the process), taking out mortgages, paying Council tax, sending kids to schools and generating jobs indirectly by doing all of this. For example, suppose 25,000 people enter the UK to reside here permanently? They want homes: that means they either rent (money to UK landlords and more tax for the IR), or they buy (money to UK lenders and often to UK builders, money on furnishings to UK shops); they want a car or two (more money for the UK's show rooms), they may open a shop (rates paid to the Council, possibly generating a few local jobs) or any other business; they may have children (family shopping bills go to UK shops and stores, and schools get filled and not closed), and so on.
What is the problem with any of this?
And to answer your question - did we ask if the countries we invaded minded most awfully that we did so? Do you think any government CONSULTS its population on who to let in and who to keep out?