Employees of the European Commission made at least one complaint of sexual harassment against a colleague every week for the past five years, it has been revealed as the hashtag #MeTooEU trends online.

There were “disciplinary sanctions for inappropriate behaviour” brought against 20 Commission staff in 2012, for example, after 65 complaints were made that year, sources told The Telegraph.

Yet just four cases a year on average resulted in sanctions over the past five years – less than a third of those reported. True levels of harassment, therefore, are likely much higher as so much goes unreported.

The Commission, the European Union’s civil service and unelected executive, said it had “zero tolerance for any form of harassment” and had rules to prevent it in place since 2006.

The Telegraph said its reporters have learnt of at least one instance where a bureaucrat used his position to make inappropriate suggestions to a female journalist.

“I have been sexually harassed, just like millions of other women in the European Union. And I think it is about time that we very clearly say that we should not be ashamed, the perpetrators should be ashamed,” German Green MEP Terry Reintke said.

Speaking during a plenary session of the European Parliament in Strasbourg on Wednesday, she added:

“Sexual harassment is such a widespread problem all over the European Union and we will need legislative steps in order to combat this problem,” she added, calling for “a directive on the fight against violence against women”.

Swedish Green MEP Linnéa Engström said she, too, had been harassed.

“Me too. Yes, I too have been a victim of sexual harassment and abuse and I think it is very painful to have to see these people still powerful, with absolutely no impact on their position,” she said.

Last week, more than a dozen young female aides told The Sunday Times that they had been targeted by older male MEPs who groped them. They had remained silent out of fear of losing their job and being blacklisted in Brussels.

The paper’s investigation claimed that the European Parliament is a “hotbed of sexual harassment”, where senior MEPs who “feel they can do whatever they want” and prey on young women.