A dispute has arisen between Shifters Ltd. ("Shifters") and Rocktrades p.l.c. ("Rocktrades"). Shifters is a company that provides sea-going barges for hire. Rocktrades is a company specialising in the transport of minerals. Both companies are based in the United Kingdom.

Rocktrades secured a contract to remove a large quantity of powdery chalk from the cliffs of Dover (U.K.) and transport it to Calais (France). To fulfil this contract, they wished to hire a sea-going barge. They were quoted a price by Shifters in a letter which stated the carrying capacity of the barge in weight but made no mention of its carrying capacity in terms of volume. Subsequently, at a meeting, Rocktrades asked Shifters' representative, Sharon, about the carrying capacity of the barge in terms of volume. Sharon quoted a figure which was based on her honest recollection of the figure stated in the ship's documents. In reliance on this figure, Rocktrades hired the barge, signing a written contract which contained no reference to the capacity of the barge in terms of volume.

It turned out that Sharon's memory had not served her right in respect of the figure stated in the ship's documents, so her statement about the volume of the barge was wrong. The barge's true volume was very much less than the figure she quoted. As a result of this, Rocktrades had to make many more trips from Dover to Calais than they had anticipated, and lost money on their contract to ship the chalk. They now wish to claim damages from Shifters.

Shifters have told Rocktrades that there is an international convention which makes Rocktrades' activities illegal, and that the law will not allow them to profit from their wrongdoing. The Convention to which they refer is the Cliff Heritage Treaty. This was drafted by the International Society for the Preservation of Pretty Coastlines, in the wake of international concern about environmental damage caused by quarrying. Under the Convention, international transportation of minerals quarried from coastlines is prohibited. The Convention has been ratified by a large number of countries, but not by the United Kingdom.

Please guide on the following questions:

a. Can Rocktrades claim damages from Shifters for breach of contract?

b. Do Rocktrades have any additional or alternative cause of action against Shifters for their loss of profit on the contract?

c. Are Shifters correct in their belief that the Cliff Heritage Treaty will apply and what impact could it have to the claim?

d. Relevant case law (to support each of the above questions)