UN experts raised serious concerns about the risk of exploitation of migrant workers on UK farms with the Foreign Office just weeks before the visa scheme was extended.

Migrant fruit pickers who come to the UK to work on farms are being saddled with debts before they arrive. Some have reported exploitation on the farms, including punishment for not meeting targets, discrimination, and poor living and working conditions.

The workers pay middlemen who help them get jobs through the government’s seasonal worker scheme, which has been extended to 2029.

In a letter sent in March to the foreign secretary David Cameron, and only recently made public, four UN special rapporteurs expressed concerns about reports of abuse taking place through the scheme.

They said that, while the UK government recognises that migrants on the seasonal worker visa “may be more vulnerable and open to exploitation than other workers”, the oversight of the farms has been “insufficient”…

The UN special rapporteurs criticised regulators the Health and Safety Executive and the Gangmasters and Labour Abuse Authority for not appearing to “have taken timely and adequate action”.