Victims of alleged harassment at Westminster have told the BBC that others affected are still too frightened to come forward.
One victim suggested "forces are trying to scupper" plans for a new complaints system due to be published next week.
The proposals, to be debated by MPs, will only see complaints from 2017 onwards investigated.
But leader of the House of Commons, Andrea Leadsom, said she was determined to push them through.
Last autumn, Westminster allegations of harassment and bullying.
The scandal claimed the ministerial careers of two cabinet ministers and elicited promises from all of the political parties that nothing like this would ever happen again.
But many months later, three of the political activists who came forward to tell their stories told Radio 4's Today that hardly anything has changed, and that victims are still too scared to speak out.
James Greenhalgh, who says he was assaulted by an unnamed MP when he was an intern in 2012, told the BBC he knew of someone who had gone through the same ordeal but did not feel able to come forward.
He said he had no confidence in the current grievance system and "nothing had changed" in terms of the culture at Westminster.
"My view is - almost as if when allegations came out, the tide went out and exposed the nasty rock pools. The tide has come back in and no-one is acting because they can't see it," he said.
But Ms Leadsom said she wanted the new grievance and complaints procedures to be up and running before the start of the summer recess next week.
"I am focused on reaching the point when anyone can come forward and complain about any single person they work with or interact with in the knowledge the complaint will be taken seriously," she said.
"I'm absolutely determined that we will have resolution of this and in short order.
"For me the key to this is to create and promote a culture that makes this a great place to work and is a role model for other parliaments and places round the world."