Reclaiming Taxes

I apologise if this has already been asked but I couldn't find a topic about it.

I lived in the UK for 10 years between '98 and '08.  During that time I was employed and payed taxes in the UK.  Before I left I was looking into companies that advertise that as a foreigner I can claim a lot of that tax back and that they will do the leg work for you (for a fee obviously).

My questions are is this something I would be eligible to do and if so is there a certain period of time I would have to do it in (its over 8 years ago now so I might be outside of it     ).  If it is possible and I'm not out of time, can anyone tell me where to go about beginning this process as I can't find any information online about it.

Any help or knowledge shared would be greatly appreciated!  Thanks!

The time limit for claiming back overpaid income tax is four years from the end of the year of assessment. This statutory rule is in TMA 1970 Schedule 1AB paragraph 3.

But the flip side and the good news is that excess foreign tax credits carry forward for you on your US returns for 10 years.

Thank you both for the information!