Chuck Hamel, an advocate for BP workers in Alaska, wrote at the weekend to Stephen Johnson, administrator of the US Environmental Protection Agency (EPA), to report that BP had suffered two additional corrosion leaks last week, which it had not yet reported.

“They have yet to reveal the newly discovered existing leak from a hole in the same transit line at another recently excavated caribou crossing . . . barely a mile away,’’ he said in the letter, a copy of which was obtained by the FT.