Sudden serious oil leak

[Ramsden15]

I went for a drive yesterday in the van and when I arrived where I was going I noticed it was dropping a significant amount of oil from underneath.
When I got home I had a look and it was pouring from between the gearbox and engine I think.
It seemed to slow or stop leaking when I turned off the engine and it cooled down. The photo is from this morning and there's only a small drop.
Any ideas what it could be?

[lefty67]

Sounds like the rear crankshaft seal.
Put up your engine type so people can advise you better.

[kevtherev]

Photo?