By surrounding works of art with corporate logos, the values, politics and cultural contexts that brought them into being are sidelined or disregarded.
'Double, double, oil is trouble! Tar sands burn as greenwash bubbles!' The chant grew louder around the Tate Britain gallery before a BP executive dressed in a sharp suit, bright green shirt and adorned with a sun-shaped logo badge emerged.
"When shall BP meet again? In oil spills, tar sands, toxic rain?" he cackled. Another executive, dressed in yellow with the same sun-shaped badge, appeared to his right. "When the sponsorship is done, PR battle fought and won!"
This was Macbeth as you have probably never seen it staged before. Moments earlier, a fake tour guide had begun to introduce John Singer Sargent's painting of the actress, Ellen Terry, where she is dressed as the iconic Lady Macbeth.
A real-life 'Lady Macbeth' had accompanied the guide and, with the arrival of BP villains, this unsanctioned tour had unfurled into a fully-fledged Shakespearean sketch on oil and morals.
A large crowd of gallery-goers gathered, watching, laughing and applauding as the (fictional) Tate Director, 'Mr Macbeth', was tempted by the three evil BP executives into striking a dastardly sponsorship deal, to help conceal the oil company's "deadly deeds" which "spread grief and chaos, 'cross lands and seas."
An ethical spotlight
This was the latest performance by the Reclaim Shakespeare Company, a troupe of 'actor-vists' who, through Shakespeare-themed performances, have sought to shine a spotlight on the ethical issues of oil companies, such as BP and Shell, sponsoring arts and culture.
The group originally formed in 2012 when it was announced that BP would be sponsoring the Royal Shakespeare Company's (RSC) 'World Shakespeare Festival' as part of the cultural Olympiad.
Over the year, they performed a total of nine "guerilla Shakespeare" interventions by invading RSC stages just before the BP-sponsored plays.
Their alternative Shakespeare season culminated in a large-scale flashmob of a hundred people at the British Museum's 'Shakespeare: Staging the World' exhibition, which had also been sponsored by the oil company.
Dramatic resignation of two board members
This recent Macbeth-themed performance at Tate Britain though was part of ongoing protest at the Tate, and a follow-up to the dramatic resignation of two Tate members at the gallery's formal AGM last month.
'Is this a logo I see before me?' Macbeth surrounded by BP Executives. Photo: Hugh Warwick.
That evening, they resigned in disgust at the Tate's ongoing relationship with BP and lack of commitment to addressing its members' concerns on the issue.
But why has cultural sponsorship by oil companies such as BP become such a controversial, and potentially toxic, issue?
Challenging the sponsorship of arts institutions, rather than confronting BP or Royal Dutch Shell directly, might seem an unusual target of protest, particularly to those who already recognise the role of fossil fuel companies in environmental damage and their historical contribution to carbon emissions.
For those less informed about environmental issues, BP can simply appear to be a generous philanthropist and champion of the arts. In reality though, cultural sponsorship is a carefully calculated part of brand management.
In order to pursue controversial projects that require political backing, such as tar sands oil extraction or fracking in water scarce regions, large oil companies like BP require a 'social license to operate'. That is, the perception that they are responsible and socially conscious.
Particularly when many still remember the images of the Deepwater Horizon disaster in the Gulf of Mexico, securing this social license is crucial to pursuing new projects, and potentially, to remaining profitable.
Uncoupling the ties between fossil fuel companies and our much-loved cultural institutions opens the space for the unsustainable business plans of BP or Shell to be scrutinised in the cold light of day - if they were no longer 'household names', then they lose the false pretence of being 'family friendly'.
BP's association with the Tate galleries is a key strategy for preventing this happening. For example, Tate Britain's main collection has now been rebranded, with each gallery labelled as the 'BP Walk Through British Art', with the words 'Supported by BP' underneath and accompanied by a BP logo with the letters BP next to it.
For good measure, there is also a series of 'BP Spotlights', specific paintings that get some extra logos too. The pocket-sized guide booklet, which is only 24 pages long, features the letters 'BP' nineteen times. You get the idea.
With this level of brand saturation you could be mistaken for thinking that the Tate are dependent on BP for their survival. Later on, after seeing Shell's logo at the Science Museum and BP's again at the Royal Opera House, you might even begin to think that these large corporate sponsors are an essential part of the arts sector.
The arts donations are remarkably small
The reality is quite different. For example, BP have stated publicly that they would give £10 million, over 5 years, to four London institutions: the Tate, the National Portrait Gallery, the British Museum and the Royal Opera House.
Even if half of that money was given to the Tate alone, that would only amount to £1 million per year - less than 1% of the gallery's annual income. (Tate's annual income for 2013 was £123 million - see page 12 of their most recent financial statement, here).
With operating budgets of billions, often equivalent to the GDP of some small countries, these sponsors are far from generous.
Further along the Thames at the Southbank Centre, Royal Dutch Shell have nestled their brand next to the world's top orchestras by sponsoring the 'Shell Classic International' concert series.
Shell is one of many corporate sponsors there but the collective contribution of these companies still only makes up only 3-4% of the Southbank's overall budget.
A bit of perspective
To put that into perspective, Shell gave roughly 17 times the amount the Southbank gained in its total corporate sponsorship in 2009 to Nigerian Security Forces the same year - around £44.2 million.
However, there are not just financial and political issues with cultural sponsorship but ethical and aesthetic ones also. To view the ethos of a sponsor as separate from the artwork sponsored is, by extension, to suggest that that artwork is irrelevant to our contemporary situation, when the reverse is true.
In Tate Britain, the 'BP walk through British Art' currently concludes with 'The Chapman Family Collection', a set of sculptures by the Chapman Brothers that scrutinise the role of brand logos and identities and the quasi-religious place they have in contemporary society.
Elsewhere, paintings by the suffragette activist and artist, Sylvia Pankhurst, are presented as a 'BP Spotlight' display.
By surrounding works of art with corporate logos, the values, politics and cultural contexts that brought them into being are at best, sidelined, and at worst, disregarded.
Part of a growing movement: 'Art not Oil'
This recent outing by the Reclaim Shakespeare Company is not a one-off intervention but part of a growing movement exposing these issues.
During the World Shakespeare Festival, the troupe gained support from audiences, staff members and performers at the RSC, alongside coverage in the national media.
The community of performers grew from a small troupe to a vast chorus. Their arts-based performances also sit alongside a number of other innovative groups, who together form the 'Art Not Oil' coalition.
Liberate Tate, a collective of artists that have challenged BP's sponsorship of the Tate over many years, recently performed 'Parts Per Million', where 50 veiled figures paraded through the BP Walk Through British Art's chronological galleries, reciting out loud the historical increase in carbon emissions.
Other audacious performances have included 'The Gift', where a full-size wind turbine blade was carried into Tate Modern's turbine hall and left as a donation to the gallery's permanent collection.
See the film here on Vimeo: The Gift - Linkup Films
At the Southbank Centre, the Shell Out Sounds choir use harmonies and adapted song lyrics to raise awareness of Shell's injustices in Canada, Nigeria and the Arctic, during the intervals of the Shell Classic Concerts.
Enthusiastic public support
Last October though, the choir found their way into the Royal Festival Hall's choir seats and sang before the evening's concert could even begin, giving a pop-up performance, which was met with enthusiastic applause.
See and hear the sprited and notably popular performance on Youtube: Oil in the Water by Shell Out Sounds.
These groups represent a rapidly growing community that see the arts as something to reclaim from the fossil fuel industry and art-making as the means for reclaiming it.
The Macbeth performance in Tate Britain concluded with the Tate director coming to his senses, exclaiming "Out damned logo!" before performers and gallery-goers came together to eject the disgruntled BP executives from the building.
While this was a fictional outcome, the reality may not be all that distant. With petitions, actions and membership resignations, it is becoming increasingly difficult for Nick Serota at the Tate or Jude Kelly at the Southbank to claim their institutions are genuine supporters of sustainability while tacitly endorsing the fossil fuel industry.
The shift in sponsorship that we need will come from a growing consciousness, an ambitious community acting collaboratively. As the actor Stanislavski put it, 'there are no small parts, only small actors.'
Chris Garrard is a composer and musicologist, and an active member of the Art Not Oil coalition. His music often explores themes relating to the environment and social justice.
He has also written about music in relation to glacial landscapes, aesthetics and photography, and produced several articles on the issue of ethical sponsorship of arts and culture.