Solved What is this shrub or perhaps tree?

This has been growing in a shaded area of my garden for 20 yrs. Each year it seems to die back to the ground, only to grow back vigorously again.
It has hollow stems and orange sap.
It puts out fine sprays of (?yellow) flowers in July. You can see one such just beginning overlying the leaf in the picture. The leaves are so unysual, I think if you have ever seen one you will know it instantly. I have no idea what it is nor have I ever seen it before. Left to its own devices it grows to around 1.3m.

 

Macleaya cordata.... the five-seeded plume-poppy.
yes sap is orange and poisonous.

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Macleaya cordata - Wikipedia

Macleaya cordata