This paper attempts to analyse the main characteristics of the Northern Rock crisis and the responses of the Bank of England as lender of last resort. On the basis of the diagnosis about the causes and the handling of this banking crisis we detect the shortcomings prevailing in the UK prudential device. We therefore try to draw the prudential lessons of this experience. As we cannot claim to present an exhaustive picture of the crisis's implications from a prudential point of view, we chose to focus instead on the points with practical significance far beyond the UK's case.