no it doesn't, it says
Driving an unroadworthy motor vehicle may invalidate your insurance. with no mention of MOT in that statement.
http://www.direct.gov.uk/en/Motoring/OwningAVe hicle/Mot/DG_4022108
States
Your MOT certificate confirms that your vehicle, at the time of its test, (as far as can be reasonably determined without dismantling) met the minimum acceptable environmental and road safety standards required by law. It doesn�t mean that the vehicle is roadworthy for the life of the certificate and isn�t a substitute for regular maintenance.
Just because a car has an MOT doesn't mean it is roadworthy, and just because a car does not have an MOT does not make it unroadworthy .
in the event of a accident the insurers assessors will inspect the car and they will tel the insurance company if it was roadworthy regardless of having a MOT or not
No MOT does not automatically invalidate insurance, driving a unroadworthy car MAY invalidate your insurance, these things are not linked.