The rate of growth of air traffic in the London Terminal Area (T.M.A.) is such that the existing airports will be unable to handle it for more than a few years. If a safe and expeditious flow of traffic is to be maintained, even if more airports of the existing type are provided, ways must be found to increase the capacity of individual airports. In any case, it will be necessary to improve the marshalling of traffic between the airports and the air routes to prevent harmful interaction between the various activities. One solution put forward, tacitly assumed that the growth potentials of Heathrow and Gatwick airports were so limited, that a third, and subsequently a fourth, airport of similar design and capacity would be required.

The alternative solution relying on ideas yet to be proved, is more difficult to assess, since possible improvements in technology must be taken into account together with the changes in A.T.C. procedure which their adoption would permit. By 1967, this task had not received the comprehensive study afforded to en-route (Mediator) problems, and no specific operational requirements existed for electronic aids related to this T.M.A. problem.

For this reason, the fairly substantial amount of work which could have a bearing on T.M.A. problems being carried out in various R. & D. establishments and industry could not be directly related to the users' needs.