Call it, for reasons I will explain shortly, the electrician's dilemma.

Britain has just announced that it will cancel a contract that would have seen the Ministry of Justice provide prison services for Saudi Arabia.

The deal was worth £5.9 million and was controversial from the start, with Labour leader Jeremy Corbyn calling on David Cameron to scrap it because of the Kingdom's dreadful human rights record.

That's just politics, though – the opposition opposes, it's what it's for.

The row got personal, though, when Justice Secretary Michael Gove also came out against it. The Foreign Office started worrying about the diplomatic ramifications and Foreign Secretary Phillip Hammond is said to have accused him of naivety. Anyway, Gove triumphed and the deal's undone.

It is hard to feel anything but satisfaction about this. The Saudi legal system is barbarous. Floggings, beheadings and crucifixions are routine. We have been reminded of this in a timely way by the case of British  expat Karl Andree, jailed in Saudi Arabia after being caught with homemade wine and reportedly facing 360 lashes. The Saudis have denied this, but there is no doubt about the probable fate of Ali Mohammed al-Nimr, facing beheading and crucifixion for taking part in a protest. 

It beggars belief that we should want to condone such a regime by helping it to run its prisons.

So I think the right decision was eventually made. There's a point beyond which we shouldn't go if we don't have to, and I think that Michael Gove (as reported by The Times, though he hasn't said so publicly) was right: the moral compromises involved in working for Saudi Arabia are unnecessarily great.

That's not to say, however, that I have much sympathy with the moral purists for whom the issue is simply black and white; and here we come back to the electrician.

In his biography of Pope Francis, Untying the Knots, Paul Vallely writes of a visit to a prison where two Jesuits were tortured during the rule of Argentina's military junta. One of the methods used was shocking them with electric cattle goads. The guide pointed to a room where the goads were repaired when they wore out from excessive use. On one occasion, he explained, an electrician was brought in to repair them. With great bravery, he refused. So the torturers used bare wires instead, which was far more dangerous.

Vallely writes: "The electrician was horrified by the quandary in which he had been placed. Should he collude with torture by fixing the goads? Or leave the victims to be subjected to even worse treatment? After an agony of indecisions he fixed the goads."

The cancelled deal would have seen the trading arm of the National Offender Management Service, JSI, provide development programmes for Saudi Arabia's prison service. Maybe it would have helped make life better for prisoners. Maybe it would have led to a change in attitudes. Maybe it would have done a bit of good. Now it won't.

I don't dissent from the decision. I think Saudi Arabia can reform itself if it wants to, and the people who count there don't want to.

But I'm not cheering, either, because striking a blow for principle comes at a cost – and we aren't the ones who are paying it.

Follow @RevMarkWoods on Twitter.