Some of Britain’s biggest companies are bucking calls to reveal more data about executive pay, risking a fresh rift with major investors who are urging the government to combat ballooning wage inequality.Four of the 16 FTSE 100 companies that responded to a Bloomberg survey -- GlaxoSmithKline, AstraZeneca, Aviva and Anglo American -- said they won’t publish a breakdown of how much more their CEOs earn than the average worker, a measure backed by the Investment Association, whose members hold about a third of the stock represented in the benchmark index.