Dear Mark,

Yesterday, you lost $6 billion.

Even for you, one of the five richest men in the world, that’s a big chunk of change.

In the worst day since its inception, your company Facebook drained 7%, or $43 billion, of its entire value.

The reason was very simple: people suddenly don’t trust you.

Dear Mark - you aren't trusted. Monday your company lost seven percent of its value and you increasingly have a reputation for evil. But what you built with Facebook used to be inspiring

The devastating revelations about consulting firm Cambridge Analytica harvesting abusing 50 million users’ data without their consent, and using that data to try to influence, among other things, the 2016 US presidential election, are a nuclear bomb-sized dent to your integrity and credibility.

‘It takes 20 years to build a reputation,’ your friend Warren Buffett once said, ‘and five minutes to ruin it. If you think about that, you’ll do things differently.’

I bet you wished you’d thought about that warning before arriving at this dreadful place.

How bad are things for you reputationally right now?

Well, the hashtag #DeleteFacebook has been trending constantly since the news broke, and the aftershocks of this investigative earthquake are being felt all over the globe.

On Good Morning Britain, the TV show I co-host in the UK, we asked viewers in a poll today if they now viewed Facebook as a force for good or evil.

A staggering 78% voted ‘evil’.

Even Donald Trump doesn’t poll that badly in the ‘evil’ stakes.

Why has it come to this?

You were never supposed to be the kind of cynical, ruthless, capitalist pig that many now accuse you of becoming.

‘Facebook was not originally created to be a company,’ you told us. ‘When I started it from my dorm room in 2004, the idea that my roommates and I talked about all the time was a world that was more open. It was built to accomplish a social mission – to make the world a more connected place.

As for your mission, you said: ‘Our philosophy is that we care about people first.’

That sounds like a very hollow claim today.

Mark, I’m a big fan of yours.

I think the way you built one of the world’s biggest companies from a simple idea you had at Harvard is as brilliant as it is inspiring.

FLASHBACK 2004: Mark, remember how you said when you founded the company here at Harvard it was built 'to make the world a more connected place' and you said, ‘Our philosophy is that we care about people first’ Sounds hollow now

Even more impressive is the way you’ve not only kept Facebook alive as many of its tech rivals disappeared, but kept it storming ahead in a perpetual curve of massive success.

Now, your tentacles have spread into most homes in the world, an extraordinary achievement.

I have a private Facebook account, and I enjoy it.

Not for expressing my opinions – I do that on Twitter – but for sharing photos and fun stuff with family and friends.

At its purest, it’s a wonderful form of easy communication.

But call me naïve, I’ve always used it in the belief the personal information I put on it would remain private to me and the friends with whom I choose to share it.

Oh, I know you target ads at me, but I find that useful not sinister, so long as the companies aren’t getting access to all my private data.

That was always what you assured us was the case.

Now I discover I’m not just naïve but downright dumb.

For you to allow a bunch of crude, shameless conmen like Cambridge Analytica to dupe you through a third party into surrendering the prized privacy of millions of your users is not just shocking, it’s an utter disgrace.

For those conmen to then use that data to influence the US election may well turn out be a criminal act.

Mark, you allowed a bunch of crude, shameless conmen in Cambridge Analytica (CEO Alexander Nix seen here today) to dupe you into surrendering the privacy of millions of your users - and this is not your first ethical violation

Mark, you may well try to hide behind the ‘we were duped too’ defense, but as the Washington Post reminded us today, this is not your first ethical violation.

We know you allowed fake news to flood users’ news feeds throughout the 2016 presidential race, permitted ad buyers to target people with disgusting terms like ‘jew hater’, and made it possible to target housing ads to whites only.

You’ve been accused of imperialism in India, erasing historical photos like the Vietnam ‘napalm girl’, livestreaming footage of human rights abuses, misrepresenting advertising metrics and stealing rivals’ features.

It all adds up to the unsavoury conclusion that you’ve put greed before ethics and people.

And this new scandal comes at a time when many people are beginning to review their use of Facebook, and their opinion about it.

There is a mounting sense of unease about the way it encourages us to show off our vanity and prejudice. And, more worryingly, the way it influences our political beliefs and voting patterns.

This morning, I asked my three sons via our Whatsapp (owned by Facebook…) group: ‘What do you guys think of Facebook now? Do you still use it, care about it? Do your friends?’

Their answers were illuminating.

‘Well, I use it all the time and could scroll for hours through all the entertaining videos, news, viral things,’ replied the youngest, aged 17. ‘But none of the year 9-11 (aged 13-15) in my school use it at all. All about Snapchat and Instagram.’

My middle boy, a 20-year-old drama student, said: ‘I would quit it but we get all our updates from my class through a group chat, so I can’t. I think it’s become pointless, the news feed is sewage, I hate that they use algorithms on the site, and the echo chambers have to stop. But what annoys me most about it is that if I were to quit, I’d miss everything. Because Facebook is now so big, no one communicates anything verbally. I could get an invite to a party on Facebook, spend all day with the person who invited me, and never hear about it once. So if I didn’t have Facebook, I’d never know anything that was going on because people just assume you’ve seen things.’

The eldest son, a 25-year-old sports journalist, demurred. ‘Personally, I still think it is by far and away the most useful and important of all social media. Not quite as trendy with the kids, but crucial for event planning, sharing of pictures, keeping contacts (especially if you lose you phone). The other social media platforms are purely for enjoyment, keeping up to date with people’s lives.’

But he added his own note of caution: ‘It’s been diluted with useless adverts and videos. Though I did see a video of a gorilla who walks like a man today and it was great!’

There then is a multi-edged snapshot of just one family’s Facebook life, but one I suspect mirrors many others.

You’ve created a fantastic thing yet is has evolved into something too powerful for its own good; a vast, cash-guzzling entity that now imperils the very democracy you’ve always insisted you want to protect.

Mark, it’s time to be straight and open with the world, as you once vowed to be.

This Cambridge Analytica affair is too serious to shrug off, and too dangerous for us to let you shrug it off.

Go to Congress and testify honestly about what has happened.

Admit your company’s grown too big, too fast, for you to exercise proper control over it.

Concede you’ve become too greedy, focusing on making money far more than making your consumers happy and fulfilled.

Confess that by doing so, your company’s values and morality have been twisted, turned and ultimately tarnished.

Tell us exactly how you intend to repair the damage and stop this stuff happening again.

You made Facebook one of the world’s biggest and most exciting companies by being a straight talker, yet now you stand accused of being the complete opposite.

It’s not too late to go back to that guy in the dorm at Harvard.

You need to testify to Congress, concede you’ve become greedy, and that that by doing so, your company’s values and morality have been twisted, turned and tarnished. Tell us how you intend to repair the damage and prevent more. It’s not too late to go back to being this guy from the Harvard dorm

The one who cared about people first, not his wallet.

The one who wanted the world to be a more transparent place.

The one we could trust.

Because be under no illusion Mark, if you don’t come clean about all this very soon, and face the unpleasant music Facebook’s appalling conduct warrants, then you will end up with a reputation no better than that of a two-bit huckster in Times Square, scamming everyone he meets and making himself very rich in the process.

When I asked my sons what they would change if they were you Mark, the middle one replied: ‘If I were Zuckerberg, I wouldn’t change anything because he’s making so much cash and I can’t quit even if I want to.’

Is that really how you want people to perceive Facebook?

Or you?

Give Warren Buffett a call, and this time listen to him.

Kind regards,

Piers Morgan