Per Lord Kenyon CJ in Pasley v Freeman (1789) E.3 T.R.51:
All laws stand on the best and broadest basis which go to enforce moral and social duties: Though indeed it is not every moral and social duty the neglect of which is the ground of an action. For there are, which are called in the civil law, duties of imperfect obligation, for the enforcing of which no action lies. There are many cases where the pure effusion of a good mind may induce the performance of particular duties, which yet cannot be enforced by municipal laws. But there are certain duties, the non-performance of which the jurisprudence of this country has made the subject of a civil action. And I find it laid down by the Lord Ch. B. Comyns, that "an action upon the case for a deceit lies when a man does any deceit to the damage of another." He has not, indeed, cited any authority for this opinion; but his opinion alone is of great authority; since he was considered by his cotemporaries as the most able lawyer in Westminster Hall.
The test stated by Lord Herschell in Derry v Peek (1889) 14 AC 337 at 374:
First, in order to sustain an action in deceit, there must be proof of fraud and nothing short of that will suffice. Secondly, fraud is proved when it is shown that a false representation has been made (1) knowingly, (2) without belief in its truth, or (3) recklessly, careless whether it be true or false.
AIC Ltd v ITS Testing Services (UK) Ltd (The Kriti Palm)  EWCA Civ 1601, per Lord Justice Rix: