Rights to light can arise after only 20 years' use and once in place can affect the development potential of land. They are not easily overridden and injunctions or substantial damages are the expected remedies against their infringement. Discusses "Midtown Ltd v City of London Real Property Co Ltd" ([2005] EWHC 33 (Ch), Abs68690) where the defendant (C) alleged that the claimant freeholder (M) did not have a right to light relating to the part of a site adjacent to M's office building on which C intended to build, using a 1930 conveyance and the Town and Country Planning Act 1990 s237 as arguments. C also contended that the question of infringement should include artificial as well as natural light. Concludes that s237 of the Act cannot always override rights affecting a development and that the regular use of artificial light cannot prevent a right to light from being infringed although it may affect the remedy awarded. M had to settle for damages.