How to reflect tax rebates on investment

Hi There

In the UK, we have a rebate on certain investments e.g. if I invest 10k, assuming I am paying the max tax, I get 3k back as a tax rebate. How best to reflect this with custom assets so that the return is calculated appropriately?

Thanks

Is it subtracted from your tax obligation at the end of the year, or only provided for the next one? Can you send a link to an article that describes how this works?