The information above is only partly correct.
PAID EMPLOYMENT DURING TRAINING:
This is only true for part-time trainees. After graduating, If you wish to complete a two-year diploma in teaching, it is a part-time course with the majority of your time on a paid placement with a subject mentor. Only then it is essential for you to be paid whilst you are assessed on the job by classroom observers, in order to gain your teaching qualification.
QTS Versus QTLS:
To teach Psychology in colleges at A' Level, you must hold a QTLS. To teach it at GCSE (fairly new to the UK compared to the US), your QTLS will not suffice. You need a QTS instead to work with any student younger than 16.
CONFUSION OF QTS & QTLS:
QTS holders have the added advantage of teaching Psychology at both secondary AND FE level. Unfortunately, QTLS holders are not equipped to jump between the age groups in this manner.
PGCE:
This is a generic course for anyone wishing to practice as a teacher. It fails to offer you QTLS or QTS unless the university (e.g. Edge Hill) specify it. Instead, prestigious Universities such as The Institute of Education (IOE) simply offer their PGCE as a stepping stone before the trainee uploads their own lesson plans on the IFL website for NQTs, in order to gain the QTLS or QTS qualification in their own time, after gaining employment.