Arab Gulf states are reaping the benefit of record oil prices but they need to invest more in their own societies and the broader Middle East to sustain sharp growth, a ­senior banker in the region on Tuesday warned.

Khalid Abdulla-Janahi, chairman of Bahrain’s Ithmaar Bank, said the region’s middle classes had been routed by inflation and the retention of wealth among the most privileged – whether in the oil-rich Gulf states or the emerging economies of the broader Middle East.