In Scotland, the Bank of Scotland, Clydesdale Bank, and the Royal Bank of Scotland, and in Northern Ireland, the Bank of Ireland, Danske Bank, First Trust Bank, and Ulster Bank, are authorised by Parliament to issue Pound sterling bank notes. They are subject to central bank (the Bank of England) regulations concerning "ring-fenced backing assets" and are backed in part by deposits at the Bank of England. They are exchangeable with other pound notes on a one-to-one basis, and circulate freely within the United Kingdom, though not legal tender, not even in Scotland and Northern Ireland.