A British tribunal ordered Tate art galleries in London to disclose its financial ties with British oil company BP before the end of January.

Environmental activist Brendan Montague brought the case before the tribunal with support of charity group Platform. Advocates who filed a Freedom of Information request against Tate argued the gallery had a "shady" relationship with BP.

The tribunal sided in part with Montague in a decision released Monday.

"Tate shall disclose within 35 days from the date of this decision the BP sponsorship figures from 1990 to 2006 inclusive," the ruling read.

Platform described the ruling as groundbreaking and brings a three-year battle to a close. The gallery gets less than 1 percent of its sponsorship directly from BP, though the advocates questioned the numbers available publicly.

"Tate's sponsorship deal provides BP with a veneer of respectability when in reality it is trashing the climate, and involved with a series of environmental and human rights controversies all around the world," Platform campaigner Anna Galkina said in a statement Tuesday.

In September, more than 100 members of advocacy group Liberate Tate descended on the galleries of the Tate Modern in London to rally in response to a court ruling BP was "grossly negligent" in the events that led up to the 2010 spill in the Gulf of Mexico.

Activists say Tate was "hijacked" by the interests of oil companies like BP. It's not the gallery's job to push fossil fuels, but instead advocate for the arts.

The tribunal found, however, that sponsorship is "undoubtedly" in the interest of the gallery, "particularly in the current climate of reductions in public funding." The gallery had offered some information to address advocacy concerns, though the tribunal found some exemptions would counter "the real risk of prejudicial impact upon Tate's commercial interests."

Tate in a response sent to UPI said it was reviewing the decision.

"The tribunal commended Tate for being thorough and open in its approach to the case," it added.

There is a 28-day window to appeal the tribunal decision. There was no statement from BP.