I am female. A full time was job was recently advertised in writing within my organisation. I queried it with my line manager about whether it had to be full time and was told yes. I therefore did not apply. The job has actually now gone to two male colleagues and has been split between them so what was a full time role has been split into two part time roles. The colleagues who got the posts were surprised by this move as it was not discussed at their interview. Is this a case of discrimination?
Assuming nobody actively lied, there does not seem to be any discrimination.
The job description was full time. Two people applied for full time, you decided not to. Then changes happened. That your boss was not gifted with a look into the future is not discrimination. You may have a case if there are company rules to post every job that exists internally first. Then those changes would have to be posted for people to apply to. But that would not be discrimination either, it would be against company rules.
Quite honestly, even if you had applied, splitting a job between two people who are there 100% of the time and just have other tasks on their desk is still different from giving half of it to a true part-timer, who is simply not available all the time. So I don't see any discrimination even then.
Clearly the role had enough work for full time, and just from your own example they were struggling to get someone to fill it full time.
From those it's not unreasonable to conclude that they (needing the role to be filled) split it into two new part-time roles to cover the "old" one. This sort of thing happens more often then you'd imagine. You'd have to do a lot of squinting and contorting to see any discrimination there.