Lower benefits for doing the same job? Is this legal?

[voituredepompier]

I have just found out that I am on a lower job grade than colleagues (one is female so no sex discrimination). We all have the same job title but have different areas of expertise, have varying years of experience (I think I have more). This has been going on for 2 years.

I have raised it with HR, my line manager was present at the meeting and did seem genuinely surprised that I was on a lower grade although I cannot quite fathom how he did not spot the discrepancies.

HR has agreed to re assess my grade going forward. I asked for it to be readjusted retrospectively and they just laughed and said that would not be possible.

Whilst I am not querying my salary as team members have different working arrangements, it does affect the benefits that I get (e.g. the bonus level, car allowance). Am I right to insist that they adjust the benefits retrospectively (its worth around 10k) Before I launch in a get my union involved (assuming they will help), do I have a leg to stand on?

thanks

[prh47bridge]

Provided there is no discrimination involved it is perfectly legal for a company to give people different salaries and benefits for the same job. If it is an oversight you may be able to get them to adjust your benefits retrospectively but, provided they have given you your contracted salary and benefits, there is no legal requirement for them to do so.