Nigeria, July 29 -- Internal Shell documents disclosed in a United Kingdom court case have exposed what rights groups describe as years of neglected infrastructure, weak environmental oversight and attempts to minimise the cost of pollution in Nigeria's oil-producing Niger Delta, raising fresh questions over the company's environmental record before its exit from the country's onshore oil business.

The findings are contained in a new report, Nigeria: Lifting the Lid, published recently by Amnesty International and seven environmental and human rights organisations.

The report analyses confidential Shell emails, technical audits, presentations and internal reviews disclosed during ongoing legal proceedings in the UK.

It alleges that She...