I bought a pack of 25 tests (flow flex) as heading away for a week with a vulnerable person. Did a test yesterday morning and was clearly negative. Left test on the side and about 2 hours later there was a very faint line (I know you should ignore after X amount of time) repeated test with another one from the box and also found an older but in date NHS pack. Both negative.
Repeated test this morning and the exact same thing happened. What do you think? Bad batch. Negative? Positive? FWIW no symptoms just the odd sneeze!