Quick! Somebody tell Scotland Yard and Interpol! Caran has just confessed to being a master criminal!
However . . .
While an insurer can void the 'optional' part of your insurance (which tops up your policy from the compulsory 'third party' bit) for not having taxed your vehicle, they're not permitted to void the third party element. As long as you've paid the premium, you're covered.
So, while you could have been prosecuted (or given an FPN) for having an untaxed vehicle on the road, you couldn't have been prosecuted for driving without insurance.
I pay my vehicle tax by direct debit, meaning that I don't have to do anything to ensure that it's always up to date.
The website for checking that a vehicle is taxed, and that its got a valid MOT certificate (where necessary) is here:
https://vehicleenquiry.service.gov.uk/