Tesco has come under attack from anti-poverty campaigners amid accusations the supermarket broke a promise to improve the pay and working conditions of South African fruit pickers, according to a report in The Guardian.

The report says Tesco agreed three years ago to look at the plight of the workers, who are mostly women and sit at the bottom of Tesco's lengthy fruit supply chain.

The newspaper says interviews it has carried out with female workers on Tesco supplier farms near Cape Town reveal they are still only being paid South Africa’s minimum wage rather than a ‘living wage’.

The workers complained that this leaves them barely enough to feed and clothe their children. Those interviewed receive just 1,231 rand a month, equivalent to £97.90.

Under the UK's Ethical Trading Initiative, which Tesco is signed up to, the supermarket agreed to ensure that "living wages are paid" and "wages should always be enough to meet basic needs and to provide some discretionary income".

Tesco told the Guardian it sourced fruit from around 790 farms in South Africa, "representing a sizeable investment in jobs for thousands of workers, although it is up to individual suppliers to decide how many employees they take on depending on factors such as seasonal demand".

The retail giant said its ethical trade programme in South Africa went beyond "anything currently attempted by other large supermarkets".

”While there remain important challenges, we believe that the South African fruit industry with its partners, including Tesco, is making real progress on improving worker conditions,” Tesco said.

“Our responsibility on wages is to ensure that suppliers are following guidance in the ETI base code and national laws. We do not believe it would be appropriate for a non-South African organisation to dictate specific sums – particularly as the national government retains close links with unions and worker organisations.”