Millions of Euros in infrastructure funding may be clawed back by the European Union after Budapest failed to introduce an agreed traffic congestion charge.

The threat is a warning to other governments to meet funding pledges, campaigners say.

Much of the €600m spent upgrading the Budapest metro could be demanded back, according to letters obtained by a clean air pressure group under freedom of information laws.

In 2003, the EU agreed to contribute to the construction of Budapest’s fourth metro line. The deal struck between Brussels and the then socialist-liberal government of Hungary included several commitments by the city of Budapest, among them the introduction of a congestion charge to boost use the metro and reduce car journeys.

The line opened in 2014, but there is still no congestion charge. Line 4 is less popular than forecast. The national conservative government of Viktor Orban says the charge is coming. But NGOs are worried that nothing is happening.

Levego Munkacsoport (Clean Air Action Group) asked for and received the correspondence between the European Commission and Hungarian officials on the subject of the congestion charge. The latest letter from the Commission, dated 22 May 2018, says there were “no tangible supporting documents attached [to the letters of the Hungarian government]” and concludes:

“We are not in a position to confirm that the beneficiary has fulfilled all commitments they have made at the approval of the project. This situation puts the expenditure already certified for the project at risk of recovery.”

Clean Air Action Group’s Márton Vargha said:

“We have been proposing for years the implementation of a distance- and pollution-based urban road pricing system in Budapest, but to no avail. Now the Hungarian government risks not only that tens of millions of euros must be repaid, but it is also missing the opportunity to reduce the serious congestion in Budapest, to improve the city’s air quality and to get revenues for the upgrading of transport infrastructure and replacing obsolete public transport vehicles.”

Air quality coordinator for NGO Transport and Environment, Jens Müller, said:

“The Hungarian authorities have messed up a perfectly good recipe for cleaner air in Budapest, so the city’s chronic traffic problems continue. It is right that Brussels demands taxpayer money back, if promises are not met. Let this be a warning to others that want to take public money then break the bargain – you may well receive an unpleasant bill from Brussels.”