May will be the first British prime minister and first woman to attend the Gulf Co-operation Council (GCC) summit as part of her two-day trip to Bahrain, starting on Tuesday (December 6).
However, given evidence that Bahraini security forces have tortured political protesters and Saudi Arabia's sentencing of juveniles to death for their part in peaceful demos, campaigners have called on Britain to prioritize human rights over trade.
"The Bahraini authorities' orchestrated attack on the rights to free expression, assembly and association has seriously undermined the prospects of a political solution to Bahrain's domestic unrest," a joint letter written by groups such as Human Rights Watch, Reprieve and the Bahrain Institute for Rights and Democracy (BIRD) said.
"If your government is serious about its commitment to encouraging reform and dialogue, you should use this influence to press the government of Bahrain to put an immediate stop to this repression."
Theresa May says she wants to "keep our people safe" as she heads to GCC summit. Will she push UAE for explanation over torture allegations? pic.twitter.com/RbQn4UILbY— Nicholas McGeehan (@NcGeehan) December 5, 2016
The pressure on the government to act over human rights concerns in the Gulf comes amid allegations that UK programs aimed at assisting and training Bahraini police and judicial forces are ineffective and merely act PR boons for the Bahraini government.
May: 'We Must Transform the Way We Do Business'
Despite the criticism, May said the questionable human rights record of Gulf countries shouldn't be a barrier to conducting trade with them, arguing the UK should "transform the way we do business" with the region.
"As the UK leaves the EU, we should seize the opportunity to forge a new trade arrangement between the UK and the Gulf," she said. "This could transform the way we do business and lock in a new level of prosperity for our people."
Theresa May is pushing UK-GCC relations in totally the wrong direction. Partly a result of Brexit vote. https://t.co/khJHMFO7un— Brian Whitaker (@Brian_Whit) December 5, 2016
The prime minister rejected the notion that Britain should not cooperate with certain Gulf states over human rights concerns, saying such a connection could give the UK influence to shape changes in the Middle East.
"No doubt there will be some people in the UK who say we shouldn't seek stronger trade and security ties with these countries because of their record on human rights."
"But we don't uphold our values and human rights by turning our back on this issue. We achieve far more by stepping up, engaging with these countries and working with them to encourage and support their plans for reform. That is how Britain can be a force for good in the world as well as helping to keep our people safe and create new opportunities for business."
While British government officials have long defended its close ties with countries like Saudi Arabia and Bahrain, arguing that the intelligence relationship is crucial to national security, critics argue that Western countries — in their support for such Gulf countries — have justified the often brutal repression and human rights abuses carried out by the governments and law enforcement officers of their Middle Eastern allies.
Of particular concern is the ongoing sale of British weapons to Saudi Arabia, with concerns they are being used in Riyadh's military campaign in Yemen, which has been accused of violating international humanitarian law.