I'm still a very new instrument pilot, and have only done it in FAA land, but I would always carry them. The theory material for the FAA IR states that you should always carry VFR charts in case you lose comms/nav and need to procede VFR, or indeed if you for some reason need to let down without comms you can identify an area of water or similar where you can safely let down below the clouds without meeting the topography.