(1)Subject to sections 2 and 3, Ministers, when carrying out or maintaining the principal works, may—
(a)deviate laterally from the lines or situations shown on the Parliamentary plans to any extent within the limits of deviation, and
(b)deviate vertically from the levels shown on the Parliamentary sections to any extent upwards or downwards.
(2)Ministers may carry out and maintain the ancillary works only within the Act limits.