Dozens of members of parliament from 14 European countries have called for an urgent investigation into who is bankrolling US Christian right groups that have spent at least $50 million in Europe, as revealed by openDemocracy last month.

This week, a group of 51 MPs wrote to the European Commission’s vice-president Frans Timmermans asking him to “investigate the funding sources and compatibility of these organisations with EU law, fundamental rights and European values”.

In March, openDemocracy revealed that a dozen US Christian ‘fundamentalist’ groups, some of which are linked to the Trump administration and Steve Bannon, have poured in at least $50 million of ‘dark money’ into Europe over the last decade.

A number of these organisations sent teams of lobbyists to Brussels to influence EU officials, challenged laws against discrimination and hate speech, and supported campaigns against LGBT rights from the Czech Republic to Romania.

Already, these findings prompted more than 40 MEPs to write to Timmermans requesting an investigation into the influence of US Christian right groups ahead of May’s highly-anticipated European Parliament elections.

In this week’s letter, a further 51 members of national parliaments urged him to also look into these groups’ sources of funding, calling it “a matter of urgency… to protect and promote democracy, human rights, gender equality and European values”.

Irish senator Alice Mary Higgins, who signed this week’s letter, said the MPs are “outraged and concerned by the attempt of US 'dark money' to influence the functioning of European democracy” and demand “urgent action”.

Another signatory, Belgian senator Petra De Sutter, said that "we should be as concerned about [the] US Christian right attempting to buy influence in European decision-making as we are about Russian interference in our elections”.

Austrian MP Petra Bayr added that their concerns are “rooted in actual homophobic and anti-women's rights policy initiatives we have seen appear in European institutions and national parliaments over the past few years – the influence is real”.

Examples of such initiatives, cited in the MPs’ letter, include an (unsuccessful) 2016 Polish bill to ban abortion and campaigns in Bulgaria and Croatia against the ratification of the Istanbul Convention to end violence against women.

Several of the US Christian right groups analysed by openDemocracy appear to be increasingly active in campaigns against sexual and reproductive rights in Europe.

One of these groups is Alliance for Defending Freedom (ADF), which spent $12.4 million in Europe since 2008. This February, it co-hosted an event with the French group La Manif Pour Tous, previously linked to the far-right party Front National.

Ahead of the last European Parliament elections in 2014, La Manif Pour Tous launched a ‘Europe for Family’ campaign which got 230 French candidates to sign a pledge opposing marriage equality, trans rights and sex education.

ADF, along with another US Christian right group called Liberty Counsel, also supported a failed attempt to change the constitution in Romania -- to make future attempts to legislate for same-sex marriage even harder.

Another group, the American Center for Law and Justice (ACLJ), operates through European courts from its office in Strasbourg, France, intervening in numerous cases on issues including same-sex marriage, abortion rights and artificial insemination.

Last month, openDemocracy also revealed that dozens of senior European politicians, are connected to a controversial network of ultra-conservative activists that has been called an anti-LGBT ‘hate group’ in the US.

Speakers at the World Congress of Families’ events have included politicians from across Europe. Almost half of came from far-right parties in Hungary, Italy, Poland, Serbia and Spain and most of these attended in the last few years alone.

Matteo Salvini, Italy’s interior minister and leader of the far-right Lega party, was among those who addressed this year’s WCF meeting in Verona, in late March.

Shortly after the congress, Salvini hosted a meeting of several representatives of European far-right parties in Milan, where he launched a new initiative to unite nationalist and traditionalist populist parties ahead of May’s elections.

Responding to this week’s letter, from 51 national parliamentarians, the Scottish MEP Alyn Smith, who’d signed the first letter to Timmermans last month, said: “This support is welcome and adds to the pressure for a serious investigation”.

"The results of the investigation by openDemocracy are deeply concerning and as we face the European Parliament election I worry that there is still potential for groups to use dark money to distort debate and to subvert democracy in Europe”.