The preliminary survey of this camp was carried out by the local military authorities, but my hon. Friend will appreciate that, apart from the necessity of taking into account factors such as water supply, road facilities, and agricultural interests, the choice of site was limited by the operational needs of anti-aircraft defence. In order to ascertain the extra cost involved in shuttering and timbering the drains below the depth of 18 inches, it would be necessary to employ a surveyor and thus incur expense to the taxpayer which would not, I think, be justified. As regards the last part of the Question, I understand that the discovery of pockets of running sand during the progress of work is not unusual in building operations, and that investigation of the subsoil over the whole area of a site of this kind would involve expenditure out of all proportion to the results obtained. I am satisfied that in this case all reasonable steps were taken by the officers who carried out the preliminary survey.