International charity Oxfam has called for a clampdown on tax havens.

A special report by the charity said that there had been an increase in rich individuals and companies using offshore jurisdictions “to avoid paying their fair share to society.”

And it called on UK Prime Minister David Cameron to crack down on Britain’s Overseas Territories and Crown Dependencies which attract money through their tax systems.

The report added: “This has denied governments valuable resources needed to tackle poverty and inequality.”

The attack came as the World Economic Forum in Davos, Switzerland, started on Wednesday.

The Oxfam report said that British Prime Minister David Cameron had told the Davos gathering three years ago that he would lead a global effort “against aggressive avoidance in the UK and in poor countries, yet promised measures to increase transparency in British Overseas Territories and Crown Dependencies, such as the Cayman Islands and British Virgin Islands, have not been implemented.”

The Oxfam report — An economy for the one per cent — said that the wealth of the poorest half of the world’s population, 3.6 billion people, had dropped by a trillion dollars since 2010.

It added that the fall had happened despite the global population increasing by 400 million over the same timeframe.

The wealth of the richest 62 people, however, has increased by more than $1.76 trillion.

Mark Goidring, Oxfam GB chief executive, said it was unacceptable that the poorest half of the world’s population owned no more than a small group of the super-rich.

He added: “World leaders’ concern about the escalating inequality crisis has so far not translated into concrete action to ensure that those at the bottom get their fair share of economic growth.

“In a world where one in nine people go to bed hungry every night we cannot afford to carry on giving the richest an ever bigger slice of the cake.

“We need to end the era of tax havens which has allowed rich individuals and multinational companies to avoid their responsibilities to society by hiding ever-increasing amounts of money offshore.

“Tackling the veil of secrecy surrounding the UK’s network of tax havens would be a big step towards ending extreme inequality.

“Three years after he made his promise to make tax dodgers ‘wake up and smell the coffee’, it is time for David Cameron to deliver.”