Artists, musicians and green activists plan to step up protests against BP's sponsorship of Britain's most prestigious galleries and museums in the wake of the Gulf oil catastrophe.

A group calling itself Good Crude Britannia, made up of artists, poets, writers and filmmakers, will picket Tate Britain's summer party next Monday which is billed by the gallery as celebrating 20 years of BP's sponsorship.

Many of Europe's leading artists, donors and cultural supporters are expected to be greeted at the glittering annual event by Lord Browne of Madingley, chair of the Tate and former head of BP.

The planned demonstration follows protests this week by a group of artists calling themselves the Greenwash Guerrillas who distributed leaflets outside the National portrait gallery at a BP-sponsored arts event. On Tuesday, Greenpeace campaigners followed up with an "alternative exhibition" at a private viewing at the gallery.

The oil company has refused to divulge how much money it gives the arts in Britain but it is thought, along with Shell, to be one of the most generous. It is a major sponsor of the British Museum, the Tate galleries, the Royal Opera House and the National Portrait Gallery. In addition it sponsors the Almeida theatre, the National Maritime Museum, as well as the Science and Natural History Museums.

"Organisations like the National Portrait Gallery help shape public attitudes towards the big issues of the day and if the Gallery is serious about climate change then the sponsorship deal with BP has got to end," said Robin Oakley, Greenpeace's campaigns director.

In a separate development, musicians including Lady Gaga, Korn, Disturbed, Godsmack, Creed and the Backstreet Boys said they planned to boycott BP on their national tours this year.

"It is absurd that the Tate should be sponsored by a company that is as irresponsible and polluting as BP," said Matthew Herbert, an electronic artist and composer who will headline the jazz stage at Glastonbury this weekend.

Jane Trowell of Platform said: "The financial support provided by BP creates a perception of it being a cuddly corporate entity, and aims to distract us from the devastating environmental and social impacts of its global operations. Public outrage over the Deepwater Horizon spill is creating a moment for change. We hope that, as happened with the tobacco industry, it will soon come to be seen as socially unacceptable for cultural institutions to accept funding from Big Oil."

The oil industry has been a target for artists and activists for many years. Shell was widely boycotted in the 1990s for its involvement in the Nigerian government's decision to hang the writer Ken Saro-Wiwa.

Last month a group called Liberate Tate entered the gallery's main turbine hall and released dozens of black balloons attached to dead fish in protest against the Gulf oil spill. Gallery staff had to shoot the balloons down with air rifles.

In a statement, the Tate said it had an ethics committee which regularly reviewed its sponsorship deals. "BP is one of the most important sponsors of the arts in the UK supporting Tate as well as several other leading cultural institutions. Tate works with a wide range of corporate organisations and generates the majority of its funding from earned income and private sources. The board and ethics committee regularly review compliance with the policy," it said.