This looks like it thank you!Take a look here, and see if this is what you have.
It looks similar but I don't think that's native to the UK?That is actually called Canada lettuce (lactuca canadensis) and shouldn’t be fed due to the lactucarium in its sap that cause narcotic effects and cardiac arrest. There are actually several species that are similar to this one compass plant/ prickly lettuce.
Thats great thank you very much!I think it might actually be a globe or creeping thistle, rather than wild lettuce or bristly ox-tongue; ox-tongue leaves tend to be a little rounder and yours are a bit hatched and arrowhead shaped, which is common in the thistles. Or perhaps another thistle thistle/relative I’m not familiar with over here.
At any rate, they are all dandelion relatives and safe. The Tortoise Table is super conversative so that info about the “bad” stuff in the wild lettuce isn’t taken as gospel by some owners. At any rate, the properties they warn about aren’t present in the plant until it’s older; if yours is young and not super tall it should be okay. My Russian won’t eat that one when it gets older so maybe the bitter taste takes care of the issue; shortly before the time it sets the yellow flowers you see in one of the pictures is when she moves on. Of course if you are worried about it or aren’t confident what it is, no need to feed until you are sure how you feel about it. I’m sure there are owners who don’t. Do what feels safe to you.
Also, unless you have a tiny baby, the pricklies on that thistle are not harmful to your tortoise; it has incredibly strong jaws and can power through stuff you and I find ouchy.