The oil industry has been named and shamed as a laggard in global efforts to increase investment to tackle water scarcity.

Royal Dutch Shell and Exxon Mobil were both name-checked as the worst offenders for “persistently” failing to reveal water data to their investors via global disclosure group CPD.

The report found that only 37 of the 138 energy companies agreed to disclose their investments in water projects, despite growing interest in water scarcity in the boardrooms of other industries.

Across the global economy 70pc of companies reported their oversight of water issues this year, while investment in water projects such as desalination plants, reclaiming waste water or improved irrigation to avoid droughts boomed to $23.4bn of investment across 1,000 projects in 91 countries.

But according to the UN $6.4 trillion (£4.9 trillion) of investment is needed globally by 2030.

CPD gave an "A" rating to more than 70 firms this year, including companies such as drinks giant Diageo, Colgate Palmolive and Nestle.

In Colgate’s investor disclosures the toothpaste maker estimates that the ‘true’ cost of water may be 2.5 times the current retail price when the need for extra investment is taken into account.

Exxon claims that the oil and gas industry uses “far less” than the agriculture or power generation sectors, although this is concentrated in crude refining.