Leylandii can cause skin irritation in some people.
Was just about to add that. Luckily I took the time to read the thread.
It's not too bad, but a day felling one in the sun does cause some redness and irritation. As mentioned below, it is worse when in the shower or washing the sap off.
To add, many milky sap plants such as Rue can cause irritation. I'm fairly sure we don't have the likes of poison oak/ivy here.
Bracken, Ester. Our commons here were bereft of Bracken for a few years after all that, the volunteers used to come in and cut it all down for our safety. Silly business really.
Took on a Kiwi to help out at work once. He was keen, ran into a nettle patch to fetch a bit of wood. Then he started screaming he was in a wasp nest. They don't have nettles there