JoanByers, first you need to decide on the argument. Either immigrants are lazy welfare seeking leeches, or they are job-stealing slaves. It amazes me how many people argue both of these points simultaneously.
Why is it amazing?
Immigrants from Pakistan have very little in common with immigrants from Poland, one set of immigrants will bring a different set of problems, and benefits, from another set.
Second, if you actually read the studies you will see that factors such as housing costs and job displacement are factored in.
How does a study factor in that I can no longer earn as much as I could in my chosen trade, or that I can't afford to buy a house? It's nonsensical to say to somebody 'Your concerns about immigration are irrelevant, this study shows that it is fiscally positive', when faced with individual problems caused by immigration, such as a primary school where most children don't speak English, or are an in area plagued by a foreign gang.
Third, job creation is not a zero-sum game. If all the foreign owned business in the UK closed tomorrow, the economy would collapse. Economies grow and shrink with their openness to talent.
We get lots of people coming from Eastern Europe, by chance of EU membership, and we get lots from South Asia based on family ties.
Neither is based on talent.
Things like the non-dom scheme, which attracts the very wealthy, and the highly-skilled migrant scheme are designed to attract talent, and job creators.
We were not festering a decade ago, our economy was not collapsing, on the countrary it was doing very well, so this idea that we needed 3 million immigrants is absurd. Post-war Britain was very possibly a different story, but we already had a large degree of diversity a decade ago.