The paywall that separates millions from free access to scientific knowledge is finally being torn down, thanks to a radical new initiative announced by 11 European nations.

The UK, France, Italy, and eight other countries have formed a bold pact called cOAlition S, designed to ensure that from 1 January 2020, all publicly funded scientific research is freely, immediately available and fully open access (OA).

For the nations taking part, the plan represents the imminent realisation of an open access dream that began decades ago, and looks destined to signify the end of the paywall as we know it.

"'Knowledge is power' and I firmly believe that free access to all scientific publications from publicly funded research is a moral right of citizens," the EU's Commissioner for Research, Science and Innovation, Carlos Moedas, said in a statement.

"It is one of the most important political commitments on science of recent times and puts Europe at the forefront of the global transition to open science."

cOAlition S – which also involves research funding agencies from Austria, Ireland, Luxembourg, the Netherlands, Norway, Poland, Slovenia, and Sweden – is designed to deliver the goals of Plan S, first announced in July, and spearheaded by the Open Access Envoy of the European Commission, Robert-Jan Smits.

Of course, Europe has signalled these exact noble sentiments before, but this time, cOAlition S is determined to anchor their ambitious plans in reality.

"We think this could create a tipping point," the president of Science Europe, Marc Schiltz, who helped frame the plan, told Science.

"Really the idea was to make a big, decisive step – not to come up with another statement or an expression of intent."

The key principle of Plan S is that from 2020 forward, all scientific research funded by public grants awarded by the 11 nation funders must be published in compliant Open Access journals or on compliant Open Access platforms – immediately, and with no restrictions.

The chief goal is to prevent paywalls from obstructing universal access to science, which Schiltz says, as a system of knowledge, can only function properly when researchers have free, unfettered access to one another's results, findings, and ideas – themselves the fruit of taxpayers' money.

"Publication paywalls are withholding a substantial amount of research results from a large fraction of the scientific community and from society as a whole," Schiltz explains in a preamble document outlining cOAlition S's aims.

"This constitutes an absolute anomaly, which hinders the scientific enterprise in its very foundations and hampers its uptake by society… no science should be locked behind paywalls!"

While the open ideals can be applauded, executing the plan won't be easy.

Right now, the terms of Plan S would actually prevent researchers from publishing their papers in approximately 85 percent of existing journals, and even 'hybrid' journals (which publish a mixture of paywalled and OA content) would be forbidden – and in the strong terms of the preamble, "should therefore be terminated".

These dramatic changes have predictably been seized upon by traditional journal publishers.

"Implementing such a plan, in our view, would disrupt scholarly communications, be a disservice to researchers, and impinge academic freedom," a spokesperson for AAAS told Science.

There are also concerns that the shakeups could jeopardise high-quality peer-review enabled by traditional systems – something which Smits is adamant can't be allowed to happen.

"Publishers are not the enemy," he told Nature. "I want them to be part of the change."

As for how these issues can be addressed (and new platforms established) before the January 2020 deadline is unclear, but those behind cOAlition S are hoping their coordinated, international effort will be the springboard that launches science into a new, free, and truly universal epoch.

"The subscription-based model of scientific publishing emerged at a certain point in the history of science, when research papers needed extensive typesetting, layout design, printing, and when hardcopies of journals needed to be distributed throughout the world," Schiltz explains.

"There is no valid reason to maintain any kind of subscription-based business model for scientific publishing in the digital world."