Job share - unequal pay

[majormumma]

Hello I’m hoping for some advice.
I work in the head office of a very large retailer, I have worked in the company for five years in February as a permanent member of the office.
Upon returning after maternity I took a role within a new team and my salary remained the same, yet pro rata as I was moving from full time to part time.
The company does annual pay reviews whereby I was awarded a 4% increase in June.
Since then, it has come to light that my pay is over 300 pounds a month less than who I job share with.
Of late my job has ramped up, I am working on high profile things which are in the spotlight, particularly from the senior leaders. To add further fuel to the fire, before me, there were two people doing my job, now it’s just me 3 days a week.
My manager and other managers in the team fully back me but in such a big organisation there appears to always be an answer or caveat. My performance is consistently good too.
Is there any way that this could be seen as discriminatory?

To show discrimination, you'd need to prove you are paid less because of a protected characteristic ie gender, disability etc. It doesn't necessarily have to be discrimination if a person doing same job is paid more ie it could be argued they had more experience, job market at the point they were hired, negotiation skills etc.

Do any of the characteristic apply? At the very least you've an argument for a pay rise .

How are toy job share if To add further fuel to the fire, before me, there were two people doing my job, now it’s just me 3 days a week.

Random autocorrect there, spotted only as I hit post!!

You not toy

Have you asked for a pay rise?

It doesn't necessarily have to be discrimination if a person doing same job is paid more ie it could be argued they had more experience, job market at the point they were hired, negotiation skills etc.

It can, but that is a huge discrepancy for two identical roles. It's many years since I was in HR but identical admin type roles on different pay scales (as opposed to merely small performance differences) was considered a huge no-no.

Speak to ACAS, OP. Also join a union. At the very least this is worth pursuing.