MPs have released documents relating to Facebook which suggest the company deliberately suffocated rivals with its business practices.
The documents also suggest that Facebook collected user data without those users' knowledge.
The chair of the committee investigating fake news, Damian Collins MP, tweeted: "We don't feel we have had straight answers from Facebook… which is why we're releasing the documents."
The committee left an empty chair for the social network's founder Mark Zuckerberg when he refused to appear at an evidence session in Westminster last week.
Not all of the documents seized by the committee have been published.
I believe there is considerable public interest in releasing these documents. They raise important questions about how Facebook treats users data, their policies for working with app developers, and how they exercise their dominant position in the social media market.
— Damian Collins (@DamianCollins) December 5, 2018
The documents were seized in November in an unusually aggressive step by the digital, culture, media and sport (DCMS) committee.
They were reportedly taken using a little-used legal power when the boss of US software company Six4Three – which is involved in court action against Facebook in the US – came to the UK on a business trip.
The release covers 250 pages including the MPs' summary and exhibits including emails from figures including Mark Zuckerberg and internal Facebook documents.
According to Mr Collins' note, Facebook used analytics software to "conduct global surveys of the usage of mobile apps by customers… apparently without their knowledge".
Facebook is accused of using this data to assess "not just how many people had downloaded apps, but how often they used them. This knowledge helped them to decide which companies to acquire, and which to treat as a threat."
Mr Collins wrote: "The files show evidence of Facebook taking aggressive positions against apps, with the consequence that denying them access to data led to the failure of that business."
The documents show an email sent to Mr Zuckerberg about short-form video app Vine in 2013. The email asked whether or not Facebook should shut down the access of Vine – which is owned by rival social media firm Twitter – to Facebook friends data.
Mr Zuckerberg replied: "Yup, go for it."
Mr Collins further alleged that Facebook maintained "whitelisting agreements" which gave select companies preferential access to valuable user data.
The documents show Lyft, Netflix and Airbnb all being whitelisted. Mr Collins wrote: "It is not clear that there was any user consent for this, nor how Facebook decided which companies should be whitelisted or not."
The claim about whitelisting echoes the accusation made by Six4Three, from whom the documents were seized.
Six4Three is currently attempting to enter these documents as evidence in its US lawsuit with Facebook.
Facebook did not immediately respond to a request for comment, but has disputed such allegations in the past.
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Neither the documents nor Mr Collins' note referenced his claim that a Facebook engineer alerted the company to the fact that three billion data points had been accessed from Russian IP addresses in 2014, as revealed during a committee hearing last week.
At the time, a Facebook spokesperson said the source of the data access was "not from Russia", adding: "We also determined the volume of actual calls to be around six million and that the suggestion of 'billions' was inaccurate."