In section 9(1) of the [1977 c. 13.] British Airways Board Act 1977 (limit of £1,000 million on borrowing by and government investment in British Airways Board) for the words " £1,000 million " there shall be substituted the words " £1,200 million but the Secretary of State may by order increase that limit to £1,400 million and by a further order to £1,600 million. "