Remember Raif Badawi? He is the blogger who was sentenced in 2012 to 10 years in jail, and 1,000 lashes, for daring to advocate respect for human rights, secularism and democracy in his native Saudi Arabia. When he received a first batch of 50 lashes in a public square in Jeddah in 2015 it nearly killed him. An international outcry ensued. Since then, Badawi has not been flogged again. But he remains in jail.

The man who controls Badawi’s fate, crown prince Mohammed bin Salman, the de facto Saudi ruler, will be in London this week. There is no chance of him being flogged. But many in Britain and France, which he will also visit, believe Salman is due, at the very least, a serious talking-to about his regime’s continuing repression of political opponents and activists, systemic discrimination against women, routine use of torture and capital punishment and, not least, its murderous war in Yemen.

Rumours are circulating that Badawi and other selected political prisoners could soon receive a royal pardon. Salman is known to be nervous about his reception here. Protests are planned on Wednesday by groups including the Campaign Against Arms Trade. Badawi’s release would obviously be welcome. But the manipulative cynicism implicit in any sudden move to free him, coinciding with Salman’s arrival in Downing Street, should deceive nobody.

Facebook Twitter Pinterest Protesters in London campaign against the flogging of the Saudi blogger Raif Badawi. The Saudi prince controls his fate. Photograph: Facundo Arrizabalaga/EPA

Salman’s two-day visit, which includes a trip to see the royals at Windsor, raises many big issues. Theresa May has said that the meeting is about “strengthening our relationships around the world and standing up for our values”. She promised “frank” discussions about issues of mutual concern “such as regional security and the conflict and humanitarian situation in Yemen”.

This would be fine if it were believable. But in truth, the UK-Saudi alliance is pernicious, encouraging the worst in both sides, and deeply corrosive of “our values”. May’s main focus is not on the unnumbered Yemeni civilians who continue to die as a result of the Saudi-led, British-backed bombing campaign. It is not on the way Saudi counter-terrorism laws and courts are still being used to persecute human rights activists, independent journalists and dissident academics, despite Salman’s supposed reform drive. It is not on women drivers nor the persecution of the Saudi Shia Muslim minority, either.

Badawi’s release would be welcome. But the manipulative cynicism implicit in any move to free him should deceive nobody

May has three priority agenda items and of them, Brexit is foremost. Her focus is on persuading the Saudis that Britain can still be an important trading, investment and business partner after it leaves the EU. A bilateral trade pact must be near the top of Liam Fox’s things-to-do list after March next year. Before then, a key test of this post-Brexit ambition will be whether the Saudis choose the City of London over New York, Tokyo and Hong Kong for the flotation of Aramco, the state-owned oil company – potentially the most valuable IPO in history. A decision is said to be imminent. “British values” have nothing to do with it.

Second, May and her ministers are keen to maintain and expand the UK security, defence and counter-terrorism relationship. David Cameron once claimed Saudi intelligence averted terrorist attacks in Britain, and the Saudi alliance is highly valued in the fight against Islamic State, al-Qaida and other jihadist groups. Ignoring evidence that Saudi Sunni Wahhabism has played a key role in encouraging anti-western extremism, Saudi Arabia is officially viewed as Islam’s leading light.

This unhealthily irrational bias is deepening. In a policy shift led by Boris Johnson, who reportedly fancies himself as one of Salman’s best buddies, Britain is increasingly aligning itself with the hard US-Saudi line on Iran, Riyadh’s regional foe. The Foreign Office currently backs the west’s 2015 nuclear accord with Tehran, which the Saudis and Donald Trump deplore, and has worked hard in recent years to normalise relations.

But in a bow to Riyadh as well as to Washington and Tel Aviv, Britain has taken to stressing shared concerns about Iran’s expanding role in Syria and Lebanon, its support for Houthi rebels in Yemen, and its burgeoning ballistic missile programme. Likewise, Britain is loath to openly criticise the reckless Saudi blockade of Qatar, an important western ally.

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Third, May’s government wants to safeguard, and if possible increase British arms sales to Saudi Arabia, notwithstanding the controversy rightly surrounding them. Since the Yemen campaign began in 2015, the UK has reportedly licensed more than £4.6bn worth of fighter jets and bombs. These sales include Typhoon jets and Paveway IV bombs. More aircraft sales may be in the offing, especially if the Salman visit goes well. Defence jobs are important, but enough is enough.

May must stop this shameful kowtowing to an abusive, undemocratic regime and its impulsive, dictatorial young leader whose much-publicised reforms amount to superficial window-dressing and offer little in the way of fundamental change. As Kate Allen of Amnesty International says, “this visit is an opportunity for the UK to finally show some backbone when it comes to Saudi Arabia”. British and Saudi interests may coincide in some respects, but their respective values are worlds apart.

• Simon Tisdall is a freelance columnist