It does depend on the subject and university, and also some luck in having the right specialism, in the right place, and the right time.
For a Lecturership in my department (Social Science, RG university), the essential criteria include:
- A PhD
- Experience of supervising 2 PhD students to completion (as a first or second supervisor)
- At least 4 x 4 and 4 x 3 journal articles, including 18 points across a maximum of five articles obtained in this REF cycle
- Grant income as a PI or Co-I of £30K on average per year, sustained for at least 3 years
- Teaching experience as a module leader or course co-ordinator
It's definitely not a first job after PhD, although we are thinking of introducing a fixed-term early career lectureship scheme that would be a grade lower than a normal lectureship, so an equivalent level to a postdoc, to improve routes in to the profession.
Just for a postdoc, our essential criteria are a PhD and 4 x 3* articles in this REF period, and our desirable criteria include PhD supervision, grant income as a PI or Co-I, and routine teaching experience. In the past 10 years I can only recall us appointing one person as a postdoc who didn't already have previous postdoc experience.
We usually get around 50 applicants for a Lectureship, but very many of them are not appointable. We get around 80 applicants for a postdoc.
Although it is difficult to get a foot on the ladder, once you have a lecturing job, if circumstances are in your favour and you are willing to move around to trade up, it can be possible to progress quite quickly though.