The EU WhoisWho directory, which showed emails and phone numbers of high and low-level officials, now only includes the contact details of heads of unit and other staff members with higher ranks.

The directory was considered especially useful because it listed specific policy areas and funding programmes that commission officials worked on, making it easier for public affairs specialists, advocacy groups and journalists to contact people and get responses.

The main problem is that the head of unit now becomes a sort of “intermediary” between you and the official you are trying to identify or contact, said Jonathan Millins, policy advisor at the Vrije Universiteit Brussel.

But these are busy people, so they do not have the time to respond quickly.

“Often you contact the head of unit and get no response, it’s very frustrating,” said Millins. “It does nothing to promote transparency, facilitate communication, or promote good governance.”

Inge Brees, who works for the NGO Search for Common Ground, has called on the commission to consider reversing the decision as the measure is already having a negative impact.

“It has decreased your transparency as an institution overnight”, she said.

The EU Commission has justified the decision on the grounds of security and data protection reasons, arguing that they have received requests from staff members of non-managerial positions not to disclose their data on the EU WhoisWho.

“Alongside its obligations linked to transparency and accountability, the Commission has the duty to protect its staff, especially those dealing with sensitive files. To avoid that these colleagues are subject to undue pressure from external sources, the access to the names and contact details of non-management staff has been limited,” the commission said in an emailed statement.

However, the commission’s decision comes at a time when EU institutions are under higher public scrutiny.

“Timing is very bad,” said Alberto Alemanno, an EU law professor and founder of The Good Lobby.

“After Qatargate, we expected greater transparency not less”, he said, referring to a bribery scandal in Brussels which erupted last year.

For his part, Philippe Dam, EU director of the NGO Human Rights Watch, pointed out that the EU executive is sending “the wrong message” with such an anti-transparency measure that cuts access to the institution.

The Society of European Affairs Professionals (SEAP) launched a petition to ask the commission to reverse its decision.

More than 300 people have signed the petition, including lobbyists from a variety of companies, such as McDonald’s, and representatives of civil society, such as the International Rescue Committee.

Around 32,000 people work in the commission, making it by far the largest EU institution.