Very large dark coloured moth

Very large dark coloured moth

Observation - Very large dark coloured moth. Description: I was shaking out clean washing before putting it away when this extremely large dark coloured moth flew out. Wingspan of three and a half to four inches. Rested on curtains until I cupped it in my hands and released it out of the window. We are situated

I was shaking out clean washing before putting it away when this extremely large dark coloured moth flew out. Wingspan of three and a half to four inches. Rested on curtains until I cupped it in my hands and released it out of the window. We are situated on the canal towpath behind Kings Cross Station.