This paper tests for the presence of a long run asymmetric Okun’s Law relationship between regional output and regional unemployment rate in U.K. regions. The existence of cointegration is tested with a panel data version of the hidden cointegration technique suggested by Granger and Yoon. A novelty of the paper is to combine the method of hidden cointegration with a panel data method of removing crosssectional dependence. The long run Okun relationship for regions in the U.K. appears to confirm results found elsewhere in the literature on countries as a whole, although the coefficients tend to be smaller.