We have no current estimate of the annual cost to the UK economy. However, the UK Intellectual Property Office has commissioned work on patent litigation in the UK, as part of an international study. This included a review of actions by Patent Assertion Entities (PAEs) by Dr Luke McDonagh of London School of Economics. Its results showed that PAE actions in UK courts were usually unsuccessful and that their business model is not attractive if they have to run the risk of costs after losing. Fewer than a dozen cases reached the UK courts in the period 2000-08. This is a much smaller proportion than the “troll” litigation evident in the USA.