A plant. Acanthus mollis

However beware as it can behave like a weed and spread. It is very difficult to remove as the roots are deep and brittle and you always seem to leave a bit behind that the grows again.

Thanks Steragram,it is spreading like a weed,thats why i wasn't sure.Should it stay or should it go?

I have had one in my garden for a few years and it has spectacular spikes with purple/white flowers on it. You might like to see it flower before you decide.

It depends where it is really. If it has plenty of room to itself keep it if you like it, but I wouldn't have it a bed with other stuff as it pops up all over the place. It has taken me three years to stop mine appearing. (And weeds are plants too...)