The European Parliament's decision to keep documents on MEPs' expenses a secret contradicted past declarations supported by most deputies, a German MEP has said.

"This rejection of access to documents is a bad surprise against the expressed will of the European Parliament's plenary," Sven Giegold, from the parliament's Green group, told EUobserver in an emailed statement.

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Giegold: 'Citizens have the right to know how rules are made on transparency of spending tax money' (Photo: European Parliament)

"Citizens have the right to know how rules are made on transparency of spending tax money," he said.

Giegold wrote the draft version of a resolution adopted last year, which said parliament should publish documents related to internal decision making.

MEPs receive a monthly lump sum of €4,416 to cover office-related costs, but are not required to keep receipts or to return unused funds.

On 2 July, the parliament's 14 vice-presidents held a meeting in the so-called Bureau format to determine how the system ought to be reformed.

According to multiple sources, they had to choose between several degrees of reform, but decided to go for a minimal change.

EUobserver subsequently asked the parliament to make public documents related to the Bureau discussion, based on the EU's access to documents regulation.

But in a letter dated 25 July, parliament secretary general Klaus Welle told EUobserver that publishing the documents "would seriously undermine the institution's decision-making process".

He wrote that because the issue was controversial, the MEPs and staff members in the working group preparing the reform needed to be sure that their documents would remain confidential - otherwise they "would practise self-censorship in the future".

His justification was criticised as "simply shocking" by transparency and ethics campaigner Margarida Silva.

But the denial is also contrary to the wishes of the actual MEPs who receive the lump sum.

"Parliament had voted in April 2016 that in principle all documents on the agenda of its Bureau should be published online," said Giegold.

He referred to a resolution which called on the parliament "to make available the agendas and feedback notes of the meetings of committee coordinators, the Bureau and the Conference of Presidents, as well as, in principle, all documents referred to in these agendas ... by publishing them on the parliament's website".

The Conference of Presidents is a format in which political group leaders meet.

The text was adopted with an 86 percent majority (523 yes votes, 37 no votes, and 46 abstentions).

On 14 September 2017, the European Parliament adopted another non-binding text entitled 'Transparency, accountability and integrity in the EU institutions' - a draft of which had been prepared by MEP Giegold.

The text repeated the phrase on publishing documents referred to in agendas.

The 2017 resolution was supported by 368 MEPs, and rejected by 161 MEPs. Sixty of them abstained.

The opposition mainly came from the centre-right European People's Party.

The bureau agenda of the 2 July meeting specifically mentioned the existence of two documents related to the office expenses decision, which means that in principle they should be published too.

"Klaus Welle should check again if he shares the restrictive position of parliament's legal service before parliament's lawyers face another defeat in the EU court," said MEP Giegold.

"The court would probably follow its line in similar cases such as Emilio de Capitani vs. Parliament, in which, in principle, the citizens' right to know weighs heavier in comparison to the protection of the institution's decision-making process," the German politician added.

De Capitani vs. Parliament was a case in front of the Luxembourg-based Court of Justice of the EU about access to documents related to the opaque trilogue negotiations between EU institutions.

The court ruled in favour of De Capitani, saying that the parliament should make trilogue documents public when citizens asked for them.

EUobserver has appealed the parliament's decision on the expenses papers.

Last week, it said that it would respond by mid-September.