...no it's not family allowance, family allowance is now called Child Benefit, and everyone no matter how rich or poor you are get's the same rate...
Family Tax Credit ( run by the Inland revenue) was introduced a few years back to replace Working Family Credit (run by the benefits agency) ... it was introduced to encourage people to get back to work as many long term unemployed seemed to be better off on Income Support (i.e getting their rent and council tax paid and basically just sitting at home doing nothing) ...as more often than not their argument was if they were in a low paid job then they might as well just claim the benefit.... basically your just working for your benefit now...it tops up your wages , it's all very complicated how they work it out , they take into account the size of your family and all the earnings/benefits you have coming in...now while it was the benefits agency that were running the system it was fairly straight forwards and fair but since the I.R have taken over it is a complete sham, they miss calculated , overpaid many familys in the first year of the claim and then drop the bombshell that you owe them thousands of pounds while at the same time stopping any entitlement altogether ...this has left many a family on the breadline, infact I heard of the red cross dishing out food parcles in some cases....