-2- 2)(a) I invite the Committee to advise as a matter of policy their or not a bursting layer should be provided and would attention to the following points:— 1) The need for the layer to supplement the RADAR warning in reducing risk of loss of life depends largely on the effectiveness of the warning system; the Minister of Home Security is, no doubt, in a position to express an opinion on this. 2)(a) The extent to which the layer can give physical protection to the tunnels depends partly on the degree of risk of a direct hit, and partly on the protection afforded by the depth of water (varying with tide) covering the tunnels so far as I know, the latter has not been assessed.