Winchester, ancient capital of England and judged best place to live in the UK in 2006!
They are Gunneras - a non-edible member of the rhubarb family that likes wet conditions. I have some next to a pond in my garden. They are very prickly and can grow to about 10' tall, so I am always pleased when the frost sets mine back a little. The flower heads are fascinating, though - very jungly.
Now I know. There are some growing in Leeds city centre adjacent to a former canal dock and I thought they were similar to rhubarb but that was about it.
Thanks for the info-so now I know! Hadnt thught of the rhubarb connection, but now you mention it, I see it!