Investigations to find out why the engine wouldn't start revealed a broken head gasket between cylinders numbers one and two.
So, as the queen said:"Off with his head!". What we found was this classic failure of the gasket.
As the Morris Minor is a very simple car it doesn't take long to lop off his head.
It's a good thing I brought my "extended portable toolbox" and a set of spares. Including a head gasket. Examining the old gasket and head didn't show any other faults on head or block, so it seemed we were lucky and we decided to clean up the block and head and replace the gasket.
A very nice and classic copper gasket too.
With the shiny new gasket on and the head with all fittings back in place the engine started without any issue. After a test run we decided all was well now, so this Minor is back in business.