Daphne Caruana Galizia was driving away from her home in October 2017 when a bomb planted under the seat of her car was remotely triggered, killing her instantly.

Caruana Galizia was a renowned anti-corruption journalist who had published damaging revelations about Malta’s prime minister and his political allies. The stories she was working on at the time of her death might have remained unpublished were it not for Forbidden Stories, an initiative run by a global network of investigative journalists whose mission is to finish the work of who have been imprisoned or harmed. The Daphne project, published last year, was a collaborative effort between 45 journalists in 15 countries.

Independent journalists like those with Forbidden Stories have a critical role to play in our democracies: they uncover truth, hold power to account and protect one another as they do so. And yet independent journalism faces an existential crisis. Misinformation and hate speech are destabilising democracies, attacks on journalists are increasing and financial models for public interest journalism are collapsing. At a moment when authoritarian governments and other malign influences are seeking to manipulate and silence the media on an unprecedented scale, only 0.3% of global aid goes to supporting media.

Next week in London, we have a chance to change this. Many of Caruana Galizia’s peers will gather alongside more than 50 foreign ministers and a number of philanthropists for the first global conference for media freedom, co-hosted by the UK Foreign Office and the Canadian government. We will be pushing a game-changing idea that could boost robust journalism and media freedom: a $1bn (£795m) international public interest media fund.

Such a move would help to tackle the crisis facing independent journalism by funding organisations around the world. The money would support strong, diverse media platforms, and in turn protect journalists from intimidation and attack. As shown by the murder of Jamal Khashoggi, one of the only Saudi journalists to criticise the regime, and the legal harassment of Maria Ressa, one of the few voices in the Philippines to highlight President Rodrigo Duterte’s extrajudicial killings, a single journalist or organisation is much easier to silence than a vibrant community.

The fund should draw capital from government development agencies, philanthropic donors and social media platforms. For democratic governments, weak media ecosystems around the world are an untenable threat to societies, especially in and around elections. For philanthropic donors, whose mission it is to tackle some of the toughest societal problems, the need to invest in the public good that is independent journalism has never been more urgent. And for the social media platforms that have done so much damage to the business model of journalism, now is the time to support the rebuilding of the industry.

A single, international structure assembling funds from these sectors would allow for a cost-effective and coordinated approach to funding public interest media. The capital would go to organisations editorially independent from government, corporate or other influences that focus primarily on reporting in the public interest.

Recipients could be organisations like amaBhugane in South Africa, which led the Gupta leaks investigation, exposing the role of the billionaire Gupta family in the corrupt power structure of Jacob Zuma’s government. Another candidate might be Nexo, the digital news site providing explanatory, contextualized journalism in the polarised Brazil of Bolsonaro.

With a structure independent from its backers, the fund would be free from undue influence over the distribution of money. Regional offices in sub-Saharan Africa, Latin America and elsewhere would ensure a localfocus, while having a single entity to support investigative journalism around the world would allow us to test what works and learn lessons.

Funding would focus on the countries of greatest need – where advertising markets are weakest, political conditions most challenging and disinformation is having the most devastating consequences. An institution founded on these principles would protect journalism and journalists worldwide.

We urge foreign ministers, government donors and philanthropists gathering in London to consider this idea seriously, provide input to strengthen and improve it, and collaborate to make it a reality.

• Nishant Lalwani is the director for independent media at Luminate, a global philanthropic organisation with the goal of empowering people and institutions to work together to build just and fair societies.