Unfortunately it's quite common due to the layered nature of unemployment benefits in the UK to be far better off on benefits than to go into work. I know several people who work the bare minimum to qualify for all their benefits then proceed to claim them for as long as possible. One example being if you have several children, working can easily reduce your child-tax credits by an amount greater than your employment income.
The counter-argument of course is that you shouldn't have children if you can't afford to raise them, but the disincentives are there, and as crazy as it sounds people are incentivised to have a lot of children as a method of escaping work.
(Optional sad Futurama parody being: https://en.wikipedia.org/wiki/The_Cyber_House_Rules)
It should never be more beneficial for someone to sit at home than to go out and earn a living.