The token thingy on my key ring is exactly the same size as the £1 coin. Comparing the 1 euro coin with the £1 coin, they both look identical in diameter but, as said, the £1 is (noticeably) thicker. You'll have to try the thingy when you get there! Guess is it won't work because the euro trolley abroad is set too narrow to take the thicker coin/ thingy; it may be that ours work with both sometimes because the diameter is of both coins is so close the thinner euro fits .