The system also works against the self-employed. If you earn £12,000 a year self-employed you will receive, on average £2,500 less than someone who earns £12,000 in employment. I hasn't really shown up yet as most of the self-employed on UC are newly self-employed and do not have the 'earnings floor' in the first year. It will gather the others as time goes by and will then be another big problem, probably putting up unemployment, as low income self-employed (most in the first two or three years of business) cannot sustain themselves and become unemployed.
All the governments preaching about the flexibility of UC and that appears to be the one thing it isn't.