Diamond retailers in the UK and the US are failing to take seriously the issue of conflict diamonds and risk undermining United Nations-backed efforts to clean up the industry, according to a report released on Monday.

The report, Déjà vu, is the product of a survey by Amnesty International and Global Witness, a campaigning group, into the implementation by diamond jewellery retailers of the Kimberley process, the UN-sponsored initiative to prevent illicit diamond trading from fuelling wars in Africa or being a conduit for terrorist finance.