The principle of net neutrality dictates that telecoms companies treat all data equally in most circumstances. It was developed in reaction to some US operators agreeing to prioritise certain publishers' traffic for payment.
US and European regulators have been negotiating laws and regulations which would enshrine elements of net neutrality principles in law, but telecoms companies have long argued that they should be allowed to charge content providers for use of their networks, as well as charging users.
The 'save the internet' campaign has been launched by digital rights groups including European Digital Rights (EDRi) and the UK's Open Rights Group (ORG).
"The internet as we know it today gives everyone the same freedoms and chance to succeed, but without net neutrality internet providers become gatekeepers that offer a premium fast lane internet for those can pay, and the slow lane for the rest of us," said the campaign's website.
"The European Commission and Council want to adopt a regulation that would allow internet service providers (ISPs) to discriminate among customers and charge extra for different types of online services. Only those who pay more will have easy access to an audience online – killing the openness that drives the internet's social and economic success," it said.
EU authorities decided last year to enact laws safeguarding elements of the net neutrality principles and in March published a text that would form the basis of final negotiations between the European Parliament, European Commission and Council of Ministers, or the trialogue.
Under the proposals ISPs would be free to engage in "traffic management" in certain circumstances.
"Blocking or slowing down specific content or applications will be prohibited, with only a limited number of exceptions and only for as long as it is necessary," the text said. "For instance, customers may request their operator to block spam. Blocking could also be necessary to prevent cyber attacks through rapidly spreading malware."
ISPs and content providers would be free, under the proposals, to agree commercial deals that guarantee "a specific level of quality" of service by the ISPs in delivering its commercial partner's content to internet users. However, ISPs would at the same time be required to ensure that its special treatment of that content did not prevent it from delivering basic internet services to other consumers.
"After months of delay and hesitation, on 2nd March 2015, the EU member states adopted an incoherent, misleading text that would undermine the net neutrality we've all been fighting for," said the 'save the internet' campaign. "This text would create paid fast-lanes, allow price discrimination in the EU, and authorise blocking of lawful content.
“The USA have recognised the need to prevent vested interests from controlling the free flow of information," said ORG executive director Jim Killock. "Europe needs to put citizens before big business and ensure the internet remains free and open.”
Telecoms executives have said in the past that charging content providers as well as users for use of their networks is an important way of continuing to raise enough money to invest in improving the speed and performance of networks.