Evidence in financial markets of an opportunity for pure arbitrage, and therefore a violation of the law of one price, is considered an anomaly to be noted. This paper reports an apparent violation of the law of one price between UK government gilts and their separately traded principal and coupon strips over a sample period of nearly 14years. There are persistent price differences, and hence opportunities for arbitrage, after allowance for the bid-ask spread; the strips package tends to be overpriced in relation to the corresponding gilt. The price differences may, in part, be due to a lack of liquidity and stale prices in the strips market.