If you visit the HMRC website you will see that this is one of quite a few known scams and you should not visit the website contained within the e-mail or disclose any personal or payment information.

HMRC do not inform customers of tax rebates via e-mail, or invite them to complete an online form to receive a tax rebate.

It is well worth visiting the HMRC website and looking at the examples of the HMRC related scams as you will see that some of the e-mail addresses used look very plausible and as well as those purporting to be offering a rebate, there are others which suggest you have underreported your income and they ask that you download and review a tax statement document.  The website then opens an executable file on your machine and opening executable files (.exe) over the internet can potentially compromise the security on your machine.

Updated: 14th July 2010