Is this discrimination?

[Same1977]

I have worked for my company for 7 years.From the very beginning I have been giving 150 percent and I have always been told that I'm doing very well.I have been asking for a promotion and payrise for 4 years now however there hasn't been a suitable vacancy.
I had a baby 9 months ago and through the great vine I have found out that a position was created 1 months ago (we did always need it ) ,which is a step up for me .Everybody in the team knew about it and had a chance to apply.Since I'm on maternity I didn't hear anything .To add insult to injury I hear the role would have been perfeft for me but they needed someone before I came back.
Are they obliged to let you know of internal positions?

Maybe so but it's HR's responsibility to ensure that policy is followed & it's their arse on the line when OP takes the employer to tribunal for discrimination due to being on maternity leave.

Any communication about promotions etc coming from HR should have "please ensure all employees currently on maternity/paternity/adoption etc leave are advised of/forwarded this communication/opportunity" if only to cover their own arse.