in the U. K some of our coins are copper, so why are they magnetic?

Because they are not pure copper

well, it would appear that your one penny and two pence coins are partially comprised of steel… a ferrousmagnetic material.

oh, and the current coins appear to have been introduced in 1971. You’ll hafta dig for yourself to find out if steel or other magnetic ingredient was a component prior. ;-)

your 5 cent 2 cent and 1 cent coins are copper covered steel coins
http://www.euro.gov.uk/eurocoins.asp

I was wondering the same thing the other day when I was at coinstar and the machine got jammed because I had accidentally put a bunch of European coins in there. A magnet caught them.