As per Ethel, we'll find out.
If you fail to disclose, it will mean the insurance gets voided from inception - ie like you've never had insurance.
You will have to pay all costs associated with the claim - including personal injury which would potentially be thousands.
Furthermore, if the police then find out that your insurance has been cancelled due to non-disclosure, you could be landed with an IN10 (driving with no insurance).
Most insurers will accept people with a drink/drive conviction, but we don't accept people with no insurance convictions - drink driving, whilst not acceptable, could well be as a result of an oversight (ie not eating all day and just being over the limit on two pints), but driving without insurance is a deliberate act.
So disclose it and pay the increased premium for a few years.