So am I correct in assuming the new owner taxed it on the MOT that was current when we sold it and is now driving around with no MOT and has made no effort to even get one?

One possibility I have considered is does he think its a new MOT done in December 2019 and has simply not read the certificate correctly. If he takes it for an MOT its going to cost a fair bit based on the 2018 advisories regarding corrosion.

As the car has been taxed it appears that the new owner intended to use it. But if he changes his mind and sells on, he will get the unused tax back, so no loss really. You can only guess what a new owner may do.

A couple of years back I sold a 205 Garros soft-top to a keen buyer from 300 miles away. I had spent quite a bit on it over 5 years, but got my asking price which was double what I had paid. Turned out the keen buyer was a trader, and the car has been SORNed without MoT ever since, but also for sale on E-bay and Car&Classic for silly money (at least at the moment). No idea whether there have been any interested punters.

I reasonably near neighbour of mine 'forgot' to MOT their car for 9 months about a couple of years ago and was driving around quite happily, despite it failing the previous MOT on a good few items.

I see a LOT of local (illegally parked) cars on my development that have a very chequered MOT history, presumably because their owners cannot be bothered to look after them until forced to do so.

Another local person I knew quite well admitted what appeared many others were doing - they used the MOT to tell them to replace parts, especially tyres, which they let get down to the proverbial carcass before replacing.

It doesn't stop with MOT's--what about failure to tax a car? Whats to stop a high risking private seller exchanging cash with a private buyer who then acquires the vehicle -on the assumption that the two of them deal with the actual ownership and admin exchange ( tax/MOT/insurance) when the tax and mot is "next due" ?

I wouldn't mind betting it has happened.

The law regards lack of an MOT as an admin-type issue - there is a fine, but no points on your licence. Typically a fixed penalty of £100.

It takes a much more robust line on someone driving a car in dangerous condition - a bigger fine and points. Disqualification for minimum of six months if its a repeat offence. etc.

Oh I dunno, budget for new disks and pads and tyres and I would be more than happy to have a look at it. More concerned that it actually has had the oil changed regularly, as all the other service stuff can be caught up with.

When I part ex cars at 3 years old they are normally MOT'd immediately by the garage and show advisories of front pads and tyres close to legal limit. I hope the person who subsequently buys them gets these done as part of the deal, almost certainly the do, so those advisories are meaningless as its just the garage getting a ticket, as the car had been looked after and the stuff is almost certainly done.