Facebook has consistently denied allegations that it listens to its users' conversations through their phone's microphone, but a new document suggests the tech giant has not ruled out doing so in the future.

Facebook users have been sharing circumstantial evidence for several years that suggests Facebook snoops on their private conversations in order to deliver more personalised ads. In April, US lawmakers finally brought the concerns to CEO Mark Zuckerberg in a hearing about data misuse on the firm's platform.

The social media firm released a 454-page document this week to follow up with questions posed to Mr Zuckerberg, after he was criticised for evading some of the most important ones.

How to stop Facebook from revealing everything about you Show all 9 1 /9 How to stop Facebook from revealing everything about you How to stop Facebook from revealing everything about you Lock your profile down If you haven’t done this already, do it now. In Settings, hit the Privacy tab. From here, you can control who gets to see your future posts and friends list. Choose from Public, Friends, Only Me and Custom in the dropdown menu. How to stop Facebook from revealing everything about you Limit old posts Annoyingly, changing this has no effect on who’s able to see your past Facebook posts. Instead, on the Privacy page, you have to click on Limit Past Posts, then select Limit Old Posts and finally hit Confirm on the pop-up. How to stop Facebook from revealing everything about you Make yourself harder to find You can stop completely random people from adding you by selecting Friends of Friends from the dropdown menu in the Who can send you friend requests? section of the Privacy page. It’s also worth limiting who can find your Facebook profile with your number and email address. At the bottom of the page is the option to prevent search engines outside of Facebook from linking to your profile. How to stop Facebook from revealing everything about you Control access to your Timeline You can limit who gets to post things on your Timeline and who gets to see posts on your Timeline too. In Settings, go to Timeline and Tagging and edit the sections you want to lock down. How to stop Facebook from revealing everything about you Block people When you block someone, they won’t be able to see things you post on your Timeline, tag you, invite you to events or groups, start conversations with you or add you as a friend. To do it, go to Settings and Blocking. Annoyingly, you have to block people on Messenger separately. You can also add friends to your Restricted list here, which means they’ll still be friends with you but will only be able to see your public posts and things you share on a mutual friend's Timeline. How to stop Facebook from revealing everything about you Review tags One of Facebook’s handiest privacy features is the ability to review posts you’re tagged in before they appear on your Timeline. They’ll still be visible on the News Feed while they’re fresh, but won’t be tied to your profile forever. In Timeline and Tagging, enable Timeline review controls. How to stop Facebook from revealing everything about you Clean up your apps You can view a list of all of the apps you’ve connected to your Facebook account by going to Settings and Apps. The list might be longer than you expected it to be. It’s worth tidying this up to ensure things you no longer use lose access to your personal information. If you don’t want to log into websites and apps with your facebook account, scroll down and turn Platform off. How to stop Facebook from revealing everything about you Change your ad preferences You can view a list of everything Facebook thinks you’re into and tinker with your ad preferences by going to Settings and Adverts. A lot more information is displayed on the desktop site than the app, so we’d recommend doing this on a computer. How to stop Facebook from revealing everything about you Download your data Facebook lets you download all of the data it has on you, including the posts you’ve shared, your messages and photos, ads you’ve clicked on and even the IP addresses that are logged when you log in or out of the site. It’s a hell of a lot of information, which you should download to ensure you never over-share on the social network again.

During the testimony, Senator Ted Cruz asked if Facebook activates, monitors, or captures data from a microphone without a user's knowledge and consent.

Facebook responded: "No, Facebook does not engage in these practices or capture data from a microphone or camera without consent."

A follow up question asked Facebook to commit to "not using its platform to gather such audio or visual information surreptitiously." Facebook did not answer the question, instead saying: "See response to [previous] question."

The comments are unlikely to quell concerns that Facebook is spying on its users, with many convinced by experiments testing the premise.

One video from 2016, which has been viewed on YouTube more than 1.7 million times, claims to show how Facebook picked up on keywords in order to serve ads for cat food.

Rob Goldman, Facebook's vice-president of advertising, said last year that it was "just not true" that the tech giant was using people's microphones to eavesdrop on conversations.

"I run ads product at Facebook," Mr Goldman tweeted in response to a thread about people's stories on the matter. "We don't – and have never – used your microphone for ads."