In most common law jurisdictions there is a Bills of Exchange Act that codifies the law in relation to negotiable instruments, including cheques, and this Act contains a statutory definition of the term banker: banker includes a body of persons, whether incorporated or not, who carry on the business of banking’ (Section 2, Interpretation).Banks can create new money when they make a loan. New loans throughout the banking system generate new deposits elsewhere in the system. The money supply is usually increased by the act of lending, and reduced when loans are repaid faster than new ones are generated. In the United Kingdom between 1997 and 2007, there was an increase in the money supply, largely caused by much more bank lending, which served to push up property prices and increase private debt. The amount of money in the economy as measured by M4 in the UK went from £750 billion to £1700 billion between 1997 and 2007, much of the increase caused by bank lending. If all the banks increase their lending together, then they can expect new deposits to return to them and the amount of money in the economy will increase. Excessive or risky lending can cause borrowers to default, the banks then become more cautious, so there is less lending and therefore less money so that the economy can go from boom to bust as happened in the UK and many other Western economies after 2007. Although this definition seems circular, it is actually functional, because it ensures that the legal basis for bank transactions such as cheques does not depend on how the bank is structured or regulated.