"The World at War" was commissioned by Thames Television in 1969. At that time, the government had halved the levy it took on television advertising revenue, with the proviso that the money the independent television companies saved had to be reinvested in programming. Thames had a pot of money available from this tax break, which Isaacs persuaded them to use on his Second World War documentary. The series eventually took four years to produce at a cost of £900,000 (). At the time this was a record for a British television series. It was first shown in 1973 on ITV.