Sir Isaac James Hayward was a British politician who was the longest-serving leader of the London County Council. He served from 1947 until it was abolished on the expansion of London in 1965.

The London County Council (LCC) was the principal local government body for the County of London throughout its existence from 1889 to 1965, and the first London-wide general municipal authority to be directly elected. It covered the area today known as Inner London and was replaced by the Greater London Council. The LCC was the largest, most significant and most ambitious English municipal authority of its day.