Sue writes

"La Puce" wrote
The shape of the leaf of the OP pic bears no resemblance to the arum
leaves. I have a few myself and the leaf in the picture doesn't look
like the one the OT sent. The OT mentioned also 'black' spots. The
usual colours of spots on arums are lighter than the leaves and are
generally from light yellow to darker green.

Having said that I haven't got a clue what it is. Looks like the leaf
is cup shaped - like the morning glory or convolvulus.

And would there be Morning Glories with broad leaves springing up in
clumps in early Spring in a British wood??

The OP's picture wasn't really showing the plant he needs to identify at
a very good angle, but Arum maculatum *does* often have dark markings,
either spots or 'marbling' - I've got some myself.

Indeed. Stace (the accepted authority on the British Flora) says "leaf
blades appearing in early spring, often blackish-purple-spotted...".

--
Kay