Lobbyists for hire - commercial lobbyists - are a small, distinct,, accepted but minor addition to the dramatis personae of UK public policy-making. Their differentiating feature,, marking them off from other types of lobbyist., is that they are for hire and it is the feature which is the least previously researched. There is little explicit theory of commercial lobbying: it is best accounted for as an implication of neo-pluralism. Through primary fieldwork amongst them and the two groups with whom they interact - clients and decisionmakers - the nature of their hiring is analysed. They are mostly hired by large businesses and less so by public sector interests facing change. Clients show varying propensities to hire and services hired in by clients can be grouped under four headings. Commercial lobbyists are client-led and have no independent political influence. They are businesses seeking market share,, offering only what hirers want. Their work can be viewed through the prism of two ideal types: backgrounder and foregrounder. On balance, they work on the processes of policy-making rather than its contents; are less rather than more visible in the policy process; more reactive than proactive in their client relationships. They have a range of negative and positive relationships with decision-makers, who accept them in terms of supplying information otherwise difficult to access. There is no demonstrated methodology for evaluating their contribution to policy outcomes. The data suggests that this contribution is minor. But this 'minor' conclusion has to be qualified when looked at from the hirers' viewpoint: for them the hiring may help yield competitive advantage. Commercial lobbyists are corporate accessories and the source of any concern about their practices and about asymmetrical access to decision-makers lies in the nature of their relationships with other more substantial players in the UK policy process. Their role will be better understood if this process is more transparent and open.