LONDON (Reuters) - BP's strategy and sustainability chief Giulia Chierchia, the key architect of the group's ill-fated foray into renewables, will step down on June 1, the company said on Tuesday.

Activist investor Elliott had demanded her exit alongside other structural changes at the company to improve accountability, according to a source.

Chierchia will leave BP and her role will be abolished, the company said in an emailed statement accompanying its lower-than-expected first-quarter results.

"As part of our continued drive to simplify our structure, the teams within the (Strategy Sustainability & Ventures) function will be integrated into other functions that will provide clear synergies, enabling quicker decision-making and clearer accountabilities," BP said.