The Cambridge Analytica scandal involving the illegal use of personal data harvested from Facebook to influence the outcome of elections is only the latest in a long line of affairs highlighting the urgent need for measures to regulate digital platforms.

If it is to develop its full potential, in terms of generating growth and jobs and stimulating technological development, the digital revolution needs freedom.

At the same time, however, we should not forget that in our liberal democracies freedom must always go hand in hand with responsibility.

Until now, that has not always been the case. One reason lies in the dizzyingly fast pace at which digital applications develop. Another, however, can be found in the misguided ideology which regards all regulation as a brake on development. It is as if at the beginning of the last century, in order not to slow down the emergence of the car as a form of transport, a decision was taken not to introduce a highway code or traffic lights and fines for bad driving.

In reality, effective rules are the basis for balanced development: protecting individuals and the market generates trust and boosts investment, technology and growth.

Given that the platforms behave like publishers, they must also be responsible for the content they publish. They cannot be allowed to turn a blind eye to the dissemination of child pornography, the illegal sale of weapons, messages preaching radicalisation and racial hatred, terrorist propaganda, the selling of counterfeit goods or blatantly fake news items.

I have invited Mark Zuckerberg to appear in person before the European Parliament to address the concerns of 500 million EU citizens

More generally, the web giants must be subject to the same rules on the protection of workers, privacy and consumers, and on transparency, taxation and intellectual property, as all other firms. This is also essential to guarantee fair competition with traditional operators. Effective competition rules make for a properly functioning internal market, with no barriers and no misuse of dominant positions, which is so damaging to small- and medium-sized businesses and consumers.

The platforms cannot be allowed to usurp the powers of the State, levying fees and duties without paying taxes themselves. Our citizens are calling for tax justice. Some States, however, which enjoy all the benefits of the internal market, offer platforms ludicrously generous, manifestly unfair terms in an effort to persuade them to locate their headquarters on their territory.

In doing so, they damage the interests of other States, forcing them to offset lost revenue by increasing taxes or cutting social services. For that reason, as proposed by Parliament and the Commission, the web giants must be taxed where they generate value, that is to say where they win advertising contracts, sell data or perform transactions, where their content is viewed and they conduct business dealings.

Introducing effective rules also means striking the right balance between the freedom of users and their privacy.

It is unacceptable that waiving the right to privacy should be the price we have to pay for accessing online applications.

The Facebook-Cambridge Analytica scandal is a wake-up call, a reminder that politicians have a duty to prevent abuses. At the same time, it gives us an opportunity to remind our fellow citizens that the EU is protecting them.

We are at the forefront of the campaign to ensure that privacy is protected.

On May 25, new EU rules will enter into force which will, for example, guarantee the right to be forgotten, the right to be protected against unsolicited advertising and the right to know when a personal data breach has occurred and how the data in question is being used.

With a view to discussing these topics with operators and institutions, on April 25 I will be hosting, together with the European Commissioner for the Digital Economy, Mariya Gabriel, a high-level conference in Parliament’s Chamber in Brussels.

The Cambridge Analytica affair is a reminder that we must remain vigilant.

We must investigate to the fullest possible extent the claims that EU citizens’ personal data has been used to manipulate elections and other votes, starting with the Brexit referendum.

For that reason, I have invited Mark Zuckerberg to appear in person before the European Parliament to address the concerns of 500 million EU citizens. I hope that he will do everything he can to help us win back our citizens’ trust.

Antonio Tajani is president of the European Parliament.