Nigeria’s two-week military offensive in the Niger Delta has dealt a significant blow to attempts by politicians to persuade one of the region’s most formidable militant leaders and thousands of his gunmen to accept a presidential offer of amnesty.

Emmanuel Uduaghan, governor of Delta State, said he feared the military’s decision to smash camps belonging to Government Ekpemupolo – known by the nickname Tompolo – had fuelled a sense of betrayal that would lead to further retaliation against the oil industry.