“As soon as the BP thing happened, of course we had to go back to reassess our entire well-management processes, procedures and technique,” Mutiu Sunmonu, Shell’s chairman in Nigeria, told the Financial Times in an interview.

Shell, which operates in the delta, offshore and in Nigeria’s fast-growing deepwater fields, was satisfied safeguards were “robust”, Mr Sunmonu added.

Nigerian government officials have suggested that, following the BP disaster, they would look anew at environmental standards.

“If they come up with tighter regulations that are not impractical, we will comply, of course,” Mr Sunmonu said.

This week Nigeria warned ExxonMobil of the US “to show more caution” following recent offshore spills.

Most of the 2,400 oil spills involving foreign partners since 2006 occurred in the creeks where residents fish, wash and worship, according to official data.

Shell blames armed groups that have blown up pipelines and kidnapped expatriates for hampering its clean-up operations. It says 98 per cent of last year’s spills were caused by gangs who siphoned off up to 10 per cent of Nigeria’s annual production.

“Oil theft and conflict has made the problem significantly worse, but both industry and government still have serious questions to answer over some very old pipelines and spill responses,” said the Stakeholder Democracy Network, a delta activist group.

After an amnesty last year that reduced attacks, Shell accelerated its clean-up efforts, Mr Sunmonu said. “Certainly we have a significant backlog, I must admit. This year alone we have been able to remediate 86 sites already.”

Shell was spending about $1bn (€813m, £675m) to replace the Nembe Creek pipeline, he added.

The BP spill has also had repercussions in Ghana, where a number of companies are tussling to acquire US explorer Kosmos’ 23.5 per cent stake in the deepwater Jubilee field, due to begin production this year.

“It affirms our thinking that you should have a company of the stature of the big guns,” said Nana Asafo Adjaye, managing director of Ghana National Petroleum Corporation, the state oil company. “If something like this did happen, at least they would have the resources to deal with it.”

Reporting by FT