There might be a simple reason for this - that markets are pricing in permanently low short-term rates, perhaps because they expect low long-term growth. Bank of England governor Mark Carney recently said that 2.5 per cent could be the "new normal" for Bank rate. If he's right, gilt yields should stay around current levels. This is because the expectations hypothesis of the yield curve tells us that long-term yields should be equal to the average expected short-term interest rate during the lifetime of the gilt. If we expect Bank rate to average 2.5 per cent over the next 10 years, therefore, 10-year gilt yields should be 2.5 per cent - which is not far from where they are now.
This poses the question: what could happen to significantly raise yields?