Anyone aged 18-23. Even those on benefits will have their lives improved; even if they aren’t getting more money from the government under our UBI alternative the big advantage is they do not lose the UBI when they move into paid employment. This offers them support and the chance to better themselves without trapping them on a targeted benefit.
Of course all those not currently receiving any benefit will also be better off. It is particularly worth noting that there are 20,000 people aged 18-23 who are not in education, employment or training and are not receiving a benefit.