Tom Tugendhat is Chair of the Foreign Affairs Select Committee, and is MP for Tonbridge and Malling.

This week’s visit by Prince Mohammed bin Salman to London has rightly been heralded by the Foreign Secretary.  Boris Johnson’s strong relationship with the Crown Prince has been forged in a country undergoing almost revolutionary change.  The Prince’s visit to the UK should not just be used to welcome an old friend, but to turn a new page on our relationship with the Guardian of the two Holy Places.  It will also be a yardstick for our commitment to British values in our post-Brexit referendum foreign policy.

In the eight months since bin Salman became Crown Prince, Saudi Arabia has made important reforms which the government has been right to support and encourage.  But we have also witnessed the crisis in neighbouring Yemen, where a Saudi-led coalition has been mired in a three-year battle against Iranian-backed Houthi rebels.  The situation has deteriorated to the point that a panel of UN experts stated that “Yemen, as a State, has all but ceased to exist.”  Millions of Yemenis, and Saudis, look to this meeting to see an end their suffering and the end of a regional threat.

After Houthi rebels overthrew Yemen’s capital and ousted the elected government, Saudi Arabia intervened in 2015 with laudable aims of protecting their borders, restoring a legitimate government and countering Iran’s destabilising influence.  But the aims have been hard to achieve.  Despite a relentless bombing campaign by the Saudi-led coalition – averaging one airstrike every 90 minutes over nearly three years – Riyadh is no closer to achieving them.

The Houthi forces are stronger now than at any time in the conflict, and Iran’s influence is growing rather than diminishing as it continues to flout a UN arms embargo.  The conflict has created the world’s largest humanitarian catastrophe on Saudi Arabia’s doorstep. A shocking 8.4 million people are now on the brink of famine – a figure almost equivalent to the entire population of London. As long as the war in Yemen drags on, it is not only the suffering of the Yemeni people that escalates, but the threat to both our countries, and the region.

I saw from my time with the British Army in Afghanistan and Iraq that you can’t just bomb your way to victory.  Extremists prosper in the ungoverned spaces filled with rubble and grievance.  Al Qaeda and other terrorist groups are profiting from the vacuum created by the total collapse of Yemeni government institutions over three years of war.  And separatist voices are gaining credence in the south, threatening the integrity of Yemen as a united country.

From Riyadh’s perspective, none of this is solving the immediate problem of securing Saudi Arabia’s borders and preventing the neighbouring state becoming an Iranian proxy.

Instead, the Saudi blockade imposed in November 2017, which cut off access for food, fuel, medicines and humanitarian aid, failed to stem the illicit flow of weapons into Yemen and served only to draw international condemnation.  We need to work together with the region to focus international energy on meaningful efforts to enforce the arms embargo and prevent further deplorable Houthi attacks on Saudi civilians.  To do that we must break the war economy that sustains the devastating cycle of violence. Saudi Arabia’s partial lifting of the blockade and its humanitarian efforts are welcome, but there is more that the Prince could do.

Saudi generosity in the two months before Ramadan could transform the country and the political situation ending the threat of a famine the UN has warned is possible without a commitment by all parties.

The key test of friendship is ability to steer allies away from self-harm.  This week, as the Government works to reinforce our longstanding friendship with Saudi Arabia, we have the chance to help the Crown Prince away from a counterproductive military strategy and towards a political settlement.

The Prime Minister and Foreign Secretary’s statements in response to the Saudi blockade were clear: the UK’s continued support for Saudi Arabia’s efforts in Yemen will be contingent on a shift in approach by the Saudi-led coalition, because true friends are seen in times of trouble, not joy.  That is why we can call for an immediate end to all attacks on civilians, allowing vital goods into and around the country, and crucially, abandoning pre-conditions to engage constructively in peace talks.

Mohammed bin Salman’s long-term vision for his country represents bold leadership to move Saudi Arabia forward and offers hope to a new generation of Saudi citizens.  The Crown Prince could do the same for Yemenis by abandoning a failing military strategy securing in peace talks what could never be achieved in battle. For Britain, the advantage is that our remains true to our strategic and moral compass, the Government should use our alliance to help the Crown Prince change his self-defeating course.