fractional reserve banking

in case you were wondering, it is common sense that bank should be required to keep a certain fraction of its lending in reserve in simple terms, say £9 in reserve for every pond lent out, of course if a bank can securitise its lending it can get round the fractional reserve requirements, that is what Northern Rock did and when its customers wanted their money the cupboard was bare, it had swapped its securities for other equally worthless securities which turned out to be worthless pieces of paper- ah the delights of securities tradingbut we all know all this, having watched Evan davies brilliant program on the BBCp://www.bbc.co.uk/iplayer/episode/b00gtljy/The_City_Uncovered_with_Evan_Davis_Banks_and_How_to_Break_Them/