Basically, w have tax credits, because, as a previous poster has said, Gordon bottled out of actually getting employers to pay a living wage. As without a living wage, workers would die - or at any rate, sleep in tents and dress in rags, if not actually starve to death, and people want to pretend we're not heading back to the Victorian era, Labour introduced tax credits - that way, (a) the families wouldn't starve, and (b) they'd always be incredibly grateful to the Labour party for giving them these lovely benefits (= client state), and vote Labour - forgetting, of course that tax credits is just the taxpayer paying to sub the wage bill for companies.
Tax credits (and housing benefit) have allowed employers to pay shit wages, house prices and rents to shoot up, thus meaning our wages to go even less far and we have to work even longer for said employers.
Personally, I'm left wing but v v against tax credits - I'd have liked to see far higher tax thresholds eg no tax on any individual earning below about 12K at least, and for tax rebates for families earning above that. That way, people would be encouraged to work, thus aviding the benefit trap - and resultant burden on all taxpayers, and families could get by. But feeling it was their own efforts that were paying their way, not 'the state'.
Obviously, I'm in favour of benefits for those who can't work, and I'd like to see better maternity benefits r transfrable tax allowances, so those with v young children (up to age 2 at least) could afford to look after them.
I'm open-minded about the need for a higher minimum wage - certainly, all the employers claimed it would cost jobs when it came in, but there is no evidence of that.