“If the amendments are passed, there would be dire consequences for European research and the value it can bring to government, the economy and society at large”, they said.

“Social science research has demonstrated the link between unemployment and health; linked smoking in pregnancy to child birth weight; and identified the long-term socio-economic benefits to children who are breastfed. Restricting the use of personal data for these and many other types of study would limit our ability to ensure European policy making is informed by the most robust evidence base”.

They added that the new restrictions would stop scientists from maintaining contact with participants even if they have “agreed” to take part in studies and despite existing “ethical approval and … confidentiality safeguards”.

The amendments in question – on articles 81 and 83 of the bill – were introduced by the European Parliament last year.

The law is now in the final stages of EU negotiations, with the European Commission predicting that it will be finalised before the end of the year.

But the main sticking point in talks is how to harmonise data protection oversight in EU capitals rather than the nitty gritty of data use for scientific purposes.

This week’s letter was signed by 28 scientists and sent out by Science Europe – a Brussels-based NGO.

The signatories include the directors of national research foundations in Belgium, the Czech Republic, Germany, France, Ireland, Norway, Portugal, Slovakia, Slovenia, and Sweden.

The appeal comes after similar warnings from science bodies in the UK and other European states fell on deaf ears in the past 12 months.

The EU parliament has become Europe’s main advocate for data protection in a political current fuelled, in part, by revelations of US abuse of people’s personal information in the name of counter-terrorism.

The EU court in Luxembourg earlier this year also struck a blow on the side of privacy in a ruling which forces internet firms to delete people’s personal information if they file a request.

The “right to be forgotten” verdict was at first welcomed by privacy campaigners, but later attracted criticism when, for instance, convicted criminals used the new rules to whitewash their online identities.