The private sector has generally sought to structure projects in order to qualify as composite traders as such treatment is often viewed as the most tax efficient option from the perspective of the private sector. Such a route must have the co-operation of the public sector, because the project documents require agreement between the parties so that the private sector may enter the site to carry out the works and services by way of a licence. Historically, this treatment has been slightly more difficult to achieve in Northern Ireland despite the fact that the regime mirrors that of Great Britain.