One of us is a member of the Labour party and the other is a Conservative. We have our differences, but both agree that bombing Syria under present circumstances would be a high-risk and pointless endeavour which should be rejected by the House of Commons, if the prime minister unwisely seeks to put it to the vote.

The truth is that, historically, aerial bombardment usually fails to be decisive unless it supports credible ground forces. In Syria, apart from Kurds in limited areas, there are no credible, non-Islamist ground forces other than President Assad’s.

Extending our efforts to Syria would be of marginal utility at best. This is partly because the UK government has set itself against coordination with the Syrian army or the Russians, which hobbles our military from the outset. The government is in denial that intervention in Syria means deciding which is the lesser of two evils, Assad or the Islamists, and acting accordingly. If the government is not prepared to face up to this hard reality – a reality that does not apply in Iraq – then we should stay out of Syria completely.

The main reason for holding back on Syria, however, is not that it would be futile but that it would be extremely dangerous. Can we be sure that the prime minister would not seek opportunities to extend the bombing to the Syrian army as well as Isis? After all, we are constantly told that parliament was wrong to prevent the bombing of the Syrian army in 2013, and that it still remains essential to remove Assad.

The government does not accept that its preferred “moderate” forces are a fantasy and that a jihadi victory would be the only outcome if Assad were overthrown – with all the biblical-scale horrors which would flow from that for the Christians, Alawites, Shia and other minorities, as well as secular Sunnis. The Russians are criticised for concentrating their fire on the non-Isis rebels, even though this category includes groups like the powerful al-Nusra Front, an affiliate of al-Qaida. With the removal of Assad, groups like this would be like vultures at a feast. No serious analyst argues that the handful of “moderates” would be a match for the jihadis.