What is the test for assessing damages for loss of income before a plaintiff has entered into a contract?

The assessment of damages must be as pragmatic as possible in the circumstances. In Esso v. Mardon, supra, Lord Denning, M.R., had this to say of assessment at p. 16: “For all such loss he is entitled to recover damages. It is to be measured in a similar way as the loss due to a personal injury. You should look into the future so as to forecast what would have been likely to happen if he had never entered into this contract; and contrast it with his position as it is now as a result of entering into it. The future is necessarily problematical and can only be a rough-and-ready estimate. But it must be done in assessing the loss.”