Filing status

My husband is us citizen living here in uk. I am British citizen but did live and work in usa for several years, we returned here when we retired and I get a social security payment from usa paid here. He has always sent his tax return in and filed as married filing separately and claimed me as an exemption. This year we have received an adjustment to his return and they have altered him to single and only one exemption which means there is a tax liability now not much of one but still. My name is always shown on the return and my social security number but I don't send in a return because my social security is laid into my British bank account .
Should he have always filed as being single and not claimed for me? Can anyone explain this to me? We are very confused.

If you are married, your filing status should never be single so that seems very odd that they would change the return to that status. If anything, it would be married filing separately instead.

You can also claim your non resident spouse as an exemption on your Federal return, so again, it does not seem like you were in the wrong. I would check out the publication below and make sure that your spouse was properly claiming you on his return. If everything seems to be done correctly, call the IRS hotline and discuss with them to get more detail on what the error is. In some instances you can contest their findings if you believe them to be incorrect.

http://www.irs.gov/Individuals/International-Taxpayers/Nonresident-Spouse-Treated-as-a-Resident

Good luck!

Thanks for the fast reply. I have spoken to the IRS and it was a mistake. Whoever input my husband's return missed me off. Everything is now sorted by a very nice IRS man - even though I was on hold 50 minutes before I got through to him. Thanks again.