Three days before renewing my car insurance I was caught speeding (Park Road.) I was unaware that I'd been caught and when I renewed my car insurance I stated, honestly, that I didn't have any points on my licence. When I got the letter saying I'd a three point penalty the points took effect retrospectively from the day of the offence. This meant that the information I had given to the Insurance Company (in good faith) was inaccurate and invalidated my insurance policy.
not quite the ABI have an agreement between themselves to rely on good faith where appropriate and on points this is usually the case. insurance is never invalidated as the insurer has a legal obligation to insure third parties so you needn't have worried on that score. they would have just said "it would have been an extra £50, pay that and we'll sort out ya claim". if they reckon there's reasonable cause to suggest that you'd have tried to con them by deliberately not declaring then had you crashed you would have been fecked they only bother null and voiding your insurance if it's an IN10 or DR10 that you've not told them about