This would save a huge amount of beaurocracy and improve peoples attitudes to work. The security of knowing a basic payment was there, without having to fill in forms, would help the unemployed to put all their energy into job hunting instead of further damaging their self esteem. The savings in administration should leave more than enough to fund this scheme.
Instead of benefits, government pensions, tax credits etc make a subsistence payment to everyone from cradle to grave. We could work as much (or as little) as we needed for anything else. A fund would need to be set up for the few with many extra needs.