Anti-oil protesters invaded the British Museum recently to protest its sponsorship from industry giant BP.

Protesters congregated in the museum’s great court on 13 September, all dressed in black with umbrellas, to form the world “no” in giant letters.

According to the British Museum, BP has acted as its “most longstanding corporate partner”. BP – which signed a £10m (US$15.4m, €13.6m) sponsorship deal with the British Museum, National Portrait Gallery, the Tate and the Royal Opera House – has been criticised previously over sponsorship of prominent cultural establishments.

London’s Science Museum was also feeling the pressure in June after it rejected claims that it allowed oil supplier Shell – a sponsor of the institution – to influence the direction of its climate change programme.

Neither the British Museum nor BP have commented on the situation, but a member of the protest group told The Guardian: “It is important to understand that the money [BP gives] is not a gift, it is not philanthropy. It is part of their marketing budget and strategy. We have challenged them at their AGM and they have admitted it. They said they expect a return [on it].”