Well at least some of them are anyway.

Like the article said.. the 1p, 2p, 5p and 10p are magnetic, but only of certain dates.. 

https://costlycoins.co.uk/why-are-some-uk-coins-magnetic/

I forgot to add the two £1 coins that I had in to the pile, but Gregg McKenzie found that the £1 coin (with the silver in the middle of it) is somewhat magnetic, mine was a UK one which I was able to pick up, although barely, as its not got anything like as much iron in it as the rest of the coins that I tested have.

This video in reply to Greggs video: UK Coins Are Not* Magnetic!

Youll have to ignore the little grunts and burps that I made while making this video, considering that I was crouching down, leaning over, phone in one hand and magnet in the other to get the shot, while trying not to breathe too heavily throughout the entire video, maybe I should of added some soothing music to it! lol.
I need a tripod.

Some of the old silver coins (from many years ago) people used to cut chucks out of them and melt them down to make another coin up (once they had enough silver to make another one!) lol.

I was given a £1 coin by a taxi driver in change once and when I looked at it later it had a chunk ripped out of it, it was a fake, it was made out of resin or plastic, the weight and color was right and it looked real.. other than the missing chunk!.