A parliamentary committee has asked Google, Facebook and Twitter to hand over specific details about how many moderators they employ and how many abuse reports they receive for an enquiry into the impact of social media and screen use on young people.

Representatives from the three companies appeared in front of the parliamentary science and technology committee on Tuesday, where attention was focused largely on their moderation efforts – their ability to find and take down problematic content, from the clearly illegal, such as child sexual abuse imagery, to the legal but undesirable, such as bullying and low-level harassment.

As at previous hearings, MPs expressed frustration with the lack of cooperation from the technology representatives. When the Labour MP Liz Kendall asked all three witnesses for specific numbers on their moderation programmes, no answers were given.

Google UK’s head of child safety, Claire Lilley, told the committee the company had “hundreds of thousands of reports” every day, and that the number of moderators was in the thousands, “if I had to take a guess”, but was unable to provide specific figures.

Twitter’s Sinéad McSweeney, similarly, was able only to share limited numbers, telling the panel that “we’ve removed more than a million accounts for sharing terrorist content”, prompting a command from Kendall to “come back to this committee with the figures that we’re after”. McSweeney argued that the hard figures would not be “informative”, since the company increasingly uses machine learning as well as human moderators to identify bad tweets.

A Conservative member, Vicky Ford, asked for another tranche of data from the companies, to assess whether or not a German law requiring speedy action on hate speech was having a valuable effect.

“What proportion of your staff working in Europe on the issue of suspect content is now working on the German market?” Ford asked Facebook’s Karim Palant, noting that “I’ve been told it’s over 80%.”

Palant replied that the number “doesn’t sound right to me, but I don’t have the figures”, prompting another request for all three companies to provide parliament with data on what’s happened in Germany “year on year with reports of hate speech, what’s been taken down, and comparable data, so that we have some evidence”.

Parliament has had mixed success when asking for information from technology companies, which tend to be reticent to share any data beyond round, rarely-updated figures. Damian Collins, chair of the culture, media and sport select committee, this year threatened Facebook and Twitter with sanctions if they did not cooperate with an inquiry into fake news.

But the fact that the companies are headquartered in the US left them apparently immune to such threats, culminating in Mark Zuckerberg snubbing repeated demands to appear in front of the committee in favour of speaking to the European parliament instead.