AN important feature of development area policy has been the provision of factories to rent on government-sponsored trading estates and sites. The great majority of firms in these factories have been granted a rent subsidy over the first five years of their tenancy. For leases taken up in or after I95 I, this subsidy, in England and Wales, has been in the form of a precise rebate of 50 per cent of the rent in the first year, 40 per cent in the second and so on down to io per cent in the fifth year.2 Before the publication of the Second Report from the Select Committee on Estimates, Session I955-56, Development Areas, it was very unusual for a firm not to receive this rebate. Paragraph I4 of the Committee's Report, however, recommended that 'for the time being, the offer of a rebate of rent to a firm should be the exception rather than the rule'. This recommendation was accepted by the Board of Trade in the Third Special Report from the Select Committee on Estimates, Session I956-57, Development Areas, April I957, and it appears that the offer of rebates has now almost come to an end. This does not mean, however, that, when the present five-year rebates have expired, there will be an end to the practice of subsidizing rentals on trading estates. In addition to the rebate, many factories receive a further, more permanent, subsidy which, because of the accounting system used by the Board of Trade and its agencies, can be of a size unknown to the Board.3 It appears that this form of subsidization will continue, not merely for existing factories already occupied on 2i-year leases, but also for new tenants and extensions on the trading estates, because the Select Committee did not make any recommendations about these permanent subsidies, nor even examine them fully. It is the purpose of this article to try to do so. The Report of the Select Committee is a good starting-point for this survey, for, in the questioning of witnesses, much interesting data emerged about trading estate rents and rent subsidies. The informa-