"The flexibility of Britain's labour market makes stagnation slightly more tolerable in the short-term than in countries where rigid labour markets have contributed to high unemployment. Yet there is a price to pay, as many jobs are part-time or temporary; when you take account of inflation, wages overall are declining." Thus Pier Carlo Padoan, chief economist of OECD, writing in this month's Prospect magazine. Nothing remarkable there, you might say. Padoan goes on: "If economic weakness lingers, there is a risk of further polarisation between full-time employees and those in part-time, insecure, often low-paid work." Again, the statement is in one sense unremarkable - except for the important warning from…