Air pollution is now “the biggest environmental risk” to public health in Europe but governments are failing to adequately deal with the crisis, the EU Court of Auditors has found.

Europe’s air pollution limits are “much weaker” than WHO guidelines – and most EU countries do not comply with them anyway, according to the damning new report.

Toxic air kills an estimated 400,000 Europeans before their time each year – up to 40,000 of them in Britain. But the UK government has been in breach of EU air quality limits since 2010 and now faces multimillion pound fines at the European court.

“Why should anyone believe the Tories’ claims to lead a ‘Green Brexit’ when they can’t even meet basic pollution targets already set at the EU level?” he asked. “Time is running out to protect those at risk and this government has shown time and time again that it is not willing to do so.”

The UK was one of 11 countries last month accused by the European Environmental Bureau of using an “inventory adjustment” loophole to effectively raise the limit on its past nitrogen dioxide emissions.

“The government has become a danger to the British people,” Dance said.

In their audit, the EU court calls for Europe’s air quality laws to be brought in line with WHO standards, which are at least twice as exacting for particulate (PM2.5 and PM10) emissions and six times stricter for sulphur dioxide (SO2).

Janusz Wojciechowski, the audit’s lead reporter, told the Guardian that the scale of the silent death toll from poisoned air was “not acceptable”.

“We have a public health crisis in Europe because of air pollution,” he said. “More than 1,000 premature deaths every day across the EU [and] more than 1% of the daily total of deaths in the EU. This is 10 times higher than the number of car accident [deaths].”

“Air pollution should be treated as a priority by the EU,” he added. “We hope that in the next financial period it will be.”

Wojciechowski noted that the bloc currently spends €3.4bn of its cohesion funds on highly polluting biomass – almost twice as much as the €1.8bn it reserves for fighting air pollution.

The auditors’ paper advises a reassessment of Europe’s funding priorities – and a speeding up of the current six to eight year delay before referring violations of law on to the European court.

The auditors also observed widely diverging standards for pollution monitoring stations.

One, in Ostrava in the Czech Republic, did not report validated data despite exceeding its daily particulates limit 98 times in 2015. Another, close to the European commission offices in Brussels, was closed “due to works” after reporting very high nitrogen dioxide readings in 2008. It never reopened.

There was a risk that the monitoring data used by the European commission was “not always credible,” Wojciechowski said.