ive also been doing the tax on line bit for quite some time and as said normally comes very quick, if you drive the anpr camera's would still show as taxed, as all it does in check on computer and it's taxed as you have paid, the camera's that look for tax disc's are different and could show as not taxed, but this would happen till after the end of the month anyway. it would be an eagle eyed copper to spot an out of date tax disc and if you got receipt would probably let it go, as it would only be a day or two past the end of the month, that's my veiw anyway