Full transparency in expense claims made by EU lawmakers would put “big pressure” on MEPs, a lawyer for the European Parliament argued this week during a hearing at the European Court of Justice.

In 2015, a group of journalists sued the European Parliament after it refused to hand over detailed accounts of MEPs’ monthly expense claims.

Last year, approximately €450 million was spent on MEPs’ salaries, travel expenses and office costs.

During a hearing about the case this week, the Parliament’s lawyer argued that if MEPs’ expense claims were publicly available, it would impose big pressure on them.

It was completely untrue that MEPs’ expense claims weren’t already visible enough for the public to hold them to account, the lawyer continued.

The 2015 request by journalists was dismissed in part because it would be an “excessive burden” to provide the requested documentation.

It was confirmed during the three-hour-long hearing that the documents amounted to millions and were not available in electronic format. One judge described this as “quite astonishing”.

The lawyer said the European Parliament estimated it had almost 900,000 individual pieces of paper for MEPs’ travel ex-penses between 2011 and 2015.

These particular documents were kept in 48 cabinets which were filled “from ceiling to floor”, the lawyer said.

Parliament argued it had internal controls in place to allow funds which were found to be incorrectly spent to be recovered. It also said giving access to information would violate MEPs’ privacy.

This argument was rejected by the journalists’ lawyers, who made it clear the data being demanded covered MEPs professional duties, and not their private lives.

The collaboration among journalists from 28 Member States found at least 41 MEPs who pay rent to national political parties or even to their own personal account.

Transparency International said the project’s findings showed the urgent need for the European Parliament to put in place robust financial control measures regarding MEPs’ use of the General Expenditure Allowance (GEA).

A series of investigations found that in 249 cases, MEPs either said they have no offices, refused to reveal their addresses, or the locations could not otherwise be traced.