At the minute, an expired MOT doesn’t command the same offences as driving with no insurance or licence. It’s upheld and monitored by DVLA so you’re more likely to just get a hefty fine. There’s also a grey area with insurance, whereby people are under the impression their insurance isn’t valid if their MOT is out of date…as I say, its a grey area because an MOT certificate only means your vehicle was legal and road worthy at that time when the test was done. Only a matter of weeks later a vehicle can become completely un-road worthy but unless someone like VOSA or a PG9 trained Police Officer examines the vehicle or you have an accident or incident that later concludes after a formal exam that the vehicle was not road worthy, the insurance is still valid. Road Tax is the same.
There has been mention that MOT and Tax will be pushed up to the top of the list with insurance and driving licence with regards to penalties but nothing has been made formal as yet.