Tony and Uma, his sister-in-law, signed a written contract for the sale of a painting for £100,000. Tony told Uma in a telephone conversation that the painting was ‘worth £125,000’. At Uma’s request, Tony wrote on the back of the written contract ‘I guarantee the painting to be worth at least £125,000’. The written contract contained a clause which said ‘no warranty is made about the value of the painting’. Tony thought that the painting was indeed worth £125,000, though he made little effort to check the facts. The artist has fallen out of fashion in recent years, and the painting is now worth significantly less than £100,000.