I believe they can if it is parked on the Roadway and not currently registered. The local council where I live do this regularly. Generally they stick a sticker on the windscreen advising that if vehicle is not removed within 24hrs it will be towed to the Council Impound yard. They keep them there for about a month and then have the power to sell them by tender (unless you pay their storage fee and remove it before it goes out to tender).

If it has been towed you'd better chase it up otherwise you'll never see it again as it will be sold off.