Facebook granted some tech firms full access to its user data as it sought to cultivate lucrative business ties with them — long after it said it was dropping the practice because of privacy concerns, according to an explosive cache of secret documents and emails.

The social networking giant put companies like Netflix, Airbnb and Lyft on a special “white list” to sidestep privacy policies it had strengthened in 2014 and 2015 to protect its users, according to the documents, which were made public Wednesday by a UK Parliament minister.

“It is not clear that there was any user consent for this, nor how Facebook decided which companies should be whitelisted or not,” Damian Collins, chair of the UK Parliament’s Digital, Culture, Media and Sport Committee, said in a statement accompanying the email excerpts and documents.

Collins notes that a recurring theme in the 250-page cache of documents is that Facebook pushed the “idea of linking access to friends data to the financial value of the developers’ relationship with Facebook.”

Indeed, Facebook appeared to view access to user data as so valuable that CEO Mark Zuckerberg personally approved a decision to restrict a rival social networking platform from accessing it, according to internal emails.

In January 2013, Facebook VP Justin Osofsky emailed Zuckerberg about the now-defunct social media app Vine, suggesting that Facebook “shut down their friends API access.”

“Yup, go for it,” Zuckerberg responded.

The documents likewise show that Zuckerberg was enthusiastic about building relationships with developers based on a policy he called “data reciprocity,” in which developers agreed to funnel their own user data to Facebook in exchange for user data that Facebook had collected.

When developers build special apps for their users to share content, “that may be good for the world but it’s not good for us unless people also share back to Facebook,” Zuckerberg wrote.

Elsewhere, emails that showed Facebook execs earlier this year debated obscuring the fact that, through an app upgrade, they were collecting data from users of Android devices, including years’ worth of phone numbers, contact names, call lengths and text messages. Specifically, Facebook mulled a way to get the data without user opt-in.

It was “a pretty high risk thing to do from a PR perspective,” Facebook product manager Michael LeBeau wrote in a February email. “But it appears the growth team will charge ahead and do it.”

LeBeau added that he was concerned about a “negative meme” popping up regarding Facebook’s data requests, and worried it might lead to “enterprising journalists” writing stories about Facebook using “new Android update to pry into your private life in ever more terrifying ways.”

Britain’s Parliament seized the documents — which a California judge ordered to be kept under seal — from the CEO of app maker Six4Three, who was on business in the UK last month.

British lawmakers used the documents last week to press Facebook policy head Richard Allan on what they called an undermining of democratic institutions.

In a release Wednesday, Facebook accused Six4Three of “cherry-picking” documents that don’t tell the full story.

The 2014 changes prevented apps from requesting access to the info of users’ friends — but some developers were allowed to continue accessing just a list of the user’s friends, Facebook said.

It said the “extensions” granted “were short-term and only used to prevent people from losing access to specific functions as developers updated their apps.”

“We’ve never sold anyone’s data,” said Zuckerberg in a post.