What are the laws on unused cars kept on public roads

[Mestar]

Hello there, just a general enquiry. My friend's neighbour has a very old car parked outside their house which they do not use and keep it there apparently to stop other people parking there. This car is over 50 years old and has not moved now for several years. A check online shows its last MOT was nearly 6 years ago. We don't know if it is meant to have an MOT or tax or even insurance but it blocks the view of the road when my friend tries to pull off her drive and she has had several near misses in the past. The car is covered in mould and is an eyesore. Is it legal for it to be kept on the public road like this?