In message , Jeff Layman
writes
On 19/05/20 17:08, Jim S wrote:
On Tue, 19 May 2020 16:10:47 +0100, Ian Jackson wrote:

This has been growing for some time in the 'wild' part of my garden
(photo here):
https://ibb.co/TgtjQj7
It's presently around 4' 6" tall, and looks like a dark green spiky
thistle. However, there is no sign of any of the usual thistle seed
heads. Can anyone tell me what it really is?
Teasel?

It isn't a teasel. The leaves are the wrong shape, and in a teasel
there is a sort of perfoliate structure around the main stem which
collects rainwater. The OP's plant does not appear to have that.

Yes - the leaves are much more pointed, and the ends are quite spiky
(indeed quite viscious-looking!). Here are a couple more photos:
https://ibb.co/DY7D01g
https://ibb.co/WvcSxM3
--
Ian