It is far from clear how best to respond to Syrian attack

Theresa May did not state if the UK would be involved in a military campaign in Syria but she pledged to work with Britain’s “closest allies”. This might be an indication that London will approve of, not join, American air strikes.

The attack was despicable, and a reflection of Syrian ruthlessness, backed by Moscow. But beyond stating such abhorrence, it is far from clear the best way to go forward.

Russia is so widely believed to have been behind a nerve agent attack in Salisbury in England that countries around the world expelled Russian diplomats in solidarity with the UK. This was a major moment of solidarity that might yet make Moscow think twice about sponsoring criminality abroad.

But the truth of the situation is that Britain is relatively powerless against Russia. The Ukrainian situation demonstrated the limits of western power, which would only be likely to be utilised if Russia took a highly aggressive step such as invading territory in the Baltic.

In Syria, Donald Trump warned yesterday that airstrikes are imminent in Syria, saying that missiles “will be coming”.

Once again, the president’s intemperate and badly timed language raises questions as to his suitability to be in charge of major military decisions at such a sensitive time.

Furthermore, the lessons of the post 2003 Iraq invasion have been clear. Western support for a range of changes of regime has if anything made the region less safe and less stable.

And even the Conservative chair of the House of Commons defence committee (see quote opposite) is admitting that by making things difficult for President Bashar al-Assad, we will be helping evil organisations such as al Qaida.

Political leaders must in these circumstance resist sentimentality, even if that means conceding that there is little we can do to stop depraved behaviour in parts of the world.