It seems clear the UK has assisted Israel’s breaches of international law. Surely Labour can do better than deny it | Sam Fowles

Britain’s history of developing and upholding international law should be a source of pride. The UK was once at the forefront of prosecuting war crimes, enshrining international human rights and developing the Geneva conventions. Recent governments, however, treated international law with contempt: successive Conservative administrations legislated to break the EU trade agreement within months of ratification, breached the refugee convention over the Rwanda plan, and repeatedly threatened to leave the European convention on human rights.

The general election offered the opportunity for a reset. One of the Starmer government’s early acts was to discontinue the UK’s attempt to block the international criminal court arrest warrant for Benjamin Netanyahu and his defence minister, Yoav Gallant. The new prime minister also restored funding to Unrwa.

These positive moves do not, however, tell the whole story. In opposition, David Lammy called for the publication of legal advice on British arms sales to Israel. Since taking power, Lammy has claimed that publishing the advice “is a quasi-legal process and it’s important that I follow actions in the appropriate way”. The government has an absolute power to publish information under section 78 of the Freedom of Information Act 2000. The decision not to publish is a political one.

We can, however, get a hint of the government’s legal view from its submissions in the ongoing challenge to British arms sales to Israel (the Starmer administration continues to defend the case). The government’s position appears to remain, broadly, that the sales are lawful because Israel is not breaching international law. It relies heavily, however, on assurances provided by Israel itself. It is not clear, from the case papers at least, whether the UK has made any significant effort to verify Israel’s claim.

The arms sales case brought against the government concerns domestic law. But the UK also has duties (and potential liabilities) in international law. In May, the UN’s Independent International Commission of Inquiry concluded that Israel has committed war crimes and crimes against humanity. These include torture, murder, sexual violence, and using starvation of civilians as a method of warfare. In July, the International Court of Justice (ICJ) ruled Israel’s occupation of the West Bank and Gaza was unlawful. It found Israel has breached Palestinians’ rights to self-determination and entitlement to freedom from “racial discrimination and apartheid”.

In the wake of the ICJ’s ruling, the development NGO Global Justice Now instructed me to provide legal advice on whether the UK (and individuals within government) may have breached international law supporting Israel’s activities. Where a state or individual provides “aid and assistance” that facilitates a war crime, crime against humanity, or breach of other international law, then they can be treated as if they have committed the wrong themselves. If, for instance, UK weapons or intelligence have been used in operations that included torture or murder, a court may decide the UK contributed to those wrongs.

In most cases a state or individual is only liable if they have “aided and assisted” with the knowledge that their help will, “in the normal course of events”, contribute to the commission of the wrong. For the most serious offences, such as genocide or breach of the right to self-determination, it’s not necessary to prove knowledge. Much of the relationship between the UK and Israel is kept secret, so it’s impossible to know the full extent of the UK’s assistance or knowledge. There are, however, significant causes for concern.

UK “aid and assistance” to Israel goes well beyond arms sales. The UK-Israel trade agreement gives both states access to each other’s markets on favourable terms. The occupied territories are integrated into Israel’s economy. Some companies conduct business in the territories before moving the products to Israel for export. It is difficult to believe that government officials aren’t aware that facilitating trade, which allows Israel and/or Israeli companies to profit from the occupied territories, aids and assists Israel’s occupation. Rather than negotiating an even closer agreement then, one might have expected a review – especially considering an agreement that helps Israel to profit from its unlawful occupation will almost certainly place the UK in breach of international law.

The UK also shares intelligence and provides military aid (as well as selling weapons). There is cause to suggest government knows these will facilitate wrongs. The Foreign Office whistleblower, Mark Smith, has said in regard to Israel’s assault on Gaza that “anyone with a basic understanding of these things can see that war crimes are being committed … flagrantly, openly, and regularly”. In March Alicia Kearns, the (then) chair of the foreign affairs select committee, told a Conservative fundraising event that she believed the government had received legal advice stating that Israel was breaching international law.

The UN investigation concluded that Israel’s conduct reflects the Dahiya doctrine. This requires the deliberate use of disproportionate force against civilians to deter resistance. If the government has reason to believe that the Dahiya doctrine is employed in Gaza, it is difficult to deny knowledge that providing aid and assistance to Israel’s operations will “in the ordinary course of events” facilitate wrongs. While Lammy has distinguished between supplying “offensive” and “defensive” weapons, it’s worth noting that Israel’s operations in Gaza are all purportedly for “self-defence”.

There is a real possibility that the UK, or individuals herein, are guilty of aiding and assisting Israel’s proven and alleged breaches of international law. The truth lies in the information about arms sales, intelligence sharing, trade, and legal advice that the government still keeps secret from the public. Paradoxically, only the government knows for sure whether the UK is breaching international law. The UK, as a member of the UN security council, has a particular duty to model respect for the law – while the Labour government now has an opportunity and an obligation to do better than its predecessors.

• Sam Fowles is a barrister, author and broadcaster. His full legal advice to Global Justice Now is available here