Its a particular bugbear of mine how the tax system treats working families. Scandinavia has gone down the route of incentivising people to have kids and providing support to get their birth rate back up. In this country we actually make it much harder for people to have kids and support them, yet we've known for years that the whole population pyramid is broken, so theres not enough people entering the jobs market to support those reaching retirement.
Trying to fix the problem via immigration only works if you can get highly skilled individuals to come to the UK who have properly vetted qualifications and can speak a good standard of English. They then need to remain resident, pay their taxes here and spend their money within the UK economy. Unfortunately based upon my experience at least, we have a knack for making it very difficult for those with the required skill sets to get visas and ILR status, but easy for those who seem to offer little to the UK.