Theresa May’s argument that it is better to engage with unsavoury foreign governments who abuse human rights than “stand on the sidelines, sniping” has been made by British politicians since the days of South Africa’s white minority apartheid regime. Critics find it no more convincing today than it was then.

May said her visit on Tuesday to Saudi Arabia, which the UN has accused of possible war crimes in Yemen, and this week’s courtesy call by the international trade secretary, Liam Fox, on the boastfully murderous regime of Rodrigo Duterte in the Philippines were in line with her philosophy of furthering the “British national interest”.

May said: “It’s in our British national interest to have good relations around the world so we can trade around the world – that brings jobs and prosperity to the UK. It’s also in our national interest to ensure we’re working with others to maintain our safety and security.

“And yes, it’s in our national interests to ensure that the values that underpin us as Britons are values that we promote around the world –and that’s what we’re doing.”

When it comes to the Gulf states, where Britain’s arms exports industry does the bulk of its business, that’s a hard circle to square. In executing, jailing and harassing their opponents since the 2011 Arab spring uprising, Bahrain’s leaders have shown scant regard for British values. But they have welcomed British armoured vehicles and weaponry with open arms.

Similarly, the regime in Riyadh is Britain’s biggest single weapons buyer. But in human rights terms, Saudi Arabia is the new South Africa, except the state-imposed, institutional discrimination there is based on gender rather than colour. Respect for women’s rights and gender equality, as understood in the west, are largely non-existent.

Reform pledges such as allowing women to drive, dating back to 1990 when the terrified regime desperately needed US and British help against Iraq’s dictator, Saddam Hussein, remain unfulfilled. Once the heat was off, the strictly Islamic kingdom forgot promises made in a panic.

May pointedly highlighted the latest reform effort, Vision 2030, promoted by the deputy crown prince, Mohammed bin Salman, the hawkish defence minister who oversees the Saudi campaign in Yemen. Its modest, long-term goal is to increase female workforce participation from 22% to 30%. This is hardly a transformation. Social, economic and religious domination by men is set to continue indefinitely.

May also put herself forward as a role model. “I hope that people see me as a woman leader, will see what women can achieve and how women can be in significant positions ... We have already seen some changes,” she said.

May appears sincere, if a trifle naive. In any case, her focus is elsewhere. Her top priority – post-Brexit trade deals – is understood only too well by her hosts. They know the government’s political imperative, and thus its vulnerability, is to make Brexit a success. They also know that in this context, rights issues are an inconvenience for both parties. So they play along with a cynical game of paying lip service to such concerns.

A prime example was when Boris Johnson, Britain’s gaffe-prone foreign secretary, clumsily criticised Saudi “puppeteers” in their “proxy war” with Iran in Yemen, where an estimated 10,000 people have died and famine is now endemic. Riyadh just shrugged and deftly dodged a row.

For the unelected, internally unstable Saudi regime, which stands accused of failing to halt the spread of Wahhabi Islamist extremism across the Muslim world, the relationship with Britain provides a degree of international respectability and an implicit security guarantee. This was underlined by the British decision to build a naval base in Bahrain, a de facto Saudi satrapy.

May provided no evidence to support her pre-visit claim that Saudi counter-terrorism cooperation has saved “hundreds” of British lives. While her predecessor, David Cameron, made a similar, less dramatic assertion, May’s sweeping statement will look to many like another justification for turning a blind eye to Saudi abuses at home and abroad.

May’s hard-headed approach is hardly new. British governments since Margaret Thatcher have routinely placed business exports, trade and arms sales above more human concerns. When Robin Cook, the late Labour foreign secretary, tried to pursue an “ethical” foreign policy, he was widely mocked and undermined, including from within Tony Blair’s government.

But Brexit, and the resulting British neediness arising from fears of economic isolation and lost jobs after it leaves the EU, appears to be exacerbating a pre-existing tendency towards double standards. Fox’s meeting with Duterte, who proudly celebrates the murderous activities of vigilante death squads that are estimated to have killed up to 7,000 people since he took office, is a breathtaking example of what many around the world will see as cynical disregard for stated British democratic values.

May hopes her fresh-minted “global Britain” will create a new paradigm in international trade. The danger is it may also set a new standard for global hypocrisy that boosts repressive regimes everywhere.