(1) Every contract entered into by Britannia Engineering Company in relation to the Mokameh unit, or Arthur Butler and Company in relation to any of the undertakings owned but it, which has vested in the Central Government under section 3, for any service, sale or supply and in force immediately before the appointed day, shall, on and from the expiry of one hundred and eighty days from the date on which this Act receives the assent of the President, cease to have effect unless such contract is, before the expiry of that period, ratified, in writing, by the Central Government, or the Government company, and in ratifying such contract, the Central Government or the Government company may make such alternation or modification therein as it may think fit:
     Provided that the Central Government or the Government company shall not omit to ratify contract and shall not make any alternation or modification in a contract unless it is satisfied that such contract is unduly onerous or has been entered into in bad faith or is detrimental to the interests of, the Central Government or the Government company.
     (2) The Central Government or the Government company shall not omit to ratify a contract, and shall not make any alternation or modification therein, except after giving the parties to the contract a reasonable opportunity of being heard and except after recording in writing its reasons for refusal to ratify the contract or for making any alternation or modification therein.