Bolton v Mahadeva [1972] EWCA Civ 5 is an English contract law case concerning substantial performance of an obligation.

It was too cold, the heat came unevenly and it all gave off fumes.

The Brentford Deputy County Court judge, Sir Graeme Finlay, held that the contract price needed to be paid, minus a sum for the cost of putting the heating system right (a total of £446, including labour).

Sachs LJ held that Bolton was entitled to nothing because there had been no substantial performance at all.

At 1015 he said, ‘It is not merely that so very much of the work was shoddy, but it is the general ineffectiveness of it for its primary purpose that leads me to that conclusion.’