Thats not entirly true though is it?
And by not spending money here, they are hardly contributing to VAT an essential government tax.
This subject of immigration is not black and white, its not all good its not all bad.
Look, contrary to what the Keynesian morons in government would have us believe, Consumer Spending is not what grows an economy.
Production is what grows an economy. If we all doubled our output we could all have twice any many things for the same price.
Therefore it is almost immaterial if the government collects VAT on a consumption, because more consumption per se is not what we want. Increase production and higher consumption will automatically follow.
Think of it in terms of a group of shipwreck survivors on an island. That's an economy right there. All the demand stimulus in the world won't do them any good unless they produce something first. They have to fish, hunt, collect water, build shelter, - ie produce - in order to consume. It's exactly the same principle for an island with 60 million as it is for an island with 6.