Fairly unlikely, you may need to contact the particular NHS clinic/department where you got the test results done, there may have been a mix up of some sort, I'd always go private but that's beacuse the public system can often let you down.
Hi and thanks for your reply... Not quite sure what you mean though cos I am afraid here, I live in London by the way, it is possible for the test results to take up to 4 weeks to come back... Back log on the NHS and so on... Regardless though, do you know how likely is it that I could indeed have HIV even though it's been 11 years since I last had unprotected sex? Thanks!
There are no HIV tests that take that long to obtain the results.