ALL this time we thought the US was Uncle Sam, it turns out that America was actually Big Brother.

Like an Orwellian nightmare – or a Channel 4 TV show – they have been watching our every move.

Every internet search, every email, every “private” social media post, could be spied on thanks to a snooping programme known as Prism.

According to documents leaked in the last week, America’s National Security Agency has access to the servers of the big hitters of the internet world – Microsoft, Yahoo, Google, Apple and Facebook.

These companies claim to know nothing about Prism.

Time will tell how much Britain’s own eavesdroppers at GCHQ in Cheltenham had to do with the surveillance.

Prism is a massive story about the infringement of the civil liberties of millions of people. Who knows where it will lead, or which careers it will ruin?

Yet at the same time, this is a tiny tale which leaves us unmoved. Have you been talking about Prism down the pub this week?

As far as I can tell, public reaction to the story splits two ways.

Some people think “this is an appalling infringement of my civil liberties – but I’m not surprised” while others say “I’m glad for our own safety that we’re all being spied on – and I’m not surprised”.

From the most lily-livered libertarian to the most sinister securocrat, one thing we all seem to share is a total lack of shock at the scale of the snooping which has been uncovered in the last week.

Like any major US scandal of the last 40 years, the Prism story has inevitably been compared with Watergate.

I wasn’t alive when Richard Nixon’s dirty tricks were coming to light in the early 70s. But I imagine that one of the reasons Watergate was such a big story was precisely because it was a shock to learn that the US president had helped cover-up a bungled burglary.

By contrast, only the genuinely naïve could be shocked by the Prism story. I’m talking about Ronex watch-level naivety here.

Anyone with any wit realises that the internet is not a private place.

Sending an email is not like delivering a piece of snail mail. You can say anything you want in an old-fashioned letter – provided you trust the postman not to steam open the envelope before he pops it through the door.

But when you send an email, you’d be well advised to assume that someone other than the intended recipient will end up reading it.

Press the send button and the email disappears into the ether. It will arrive at the right destination, but it will also linger, somewhere in the worldwide web, somewhere where it may one day be seen by anyone from a potential spouse to a would-be employer.

Likewise, you can delete all those embarrassing pictures from Facebook, but somewhere in the deep web the images will linger.

The politically ambitious can un-tag themselves all they want, but their enemies will find those pictures eventually.

David Cameron must wake up every day and thank his lucky stars he was born in 1966 and not 1986.

Remember all the hassle that one Bullingdon Club picture has caused him? If he’d gone to Oxford in the Noughties rather than the Eighties, there’d be dozens of embarrassing snaps like that on Facebook just waiting to come back to haunt him.

I wonder, as prime ministers get steadily younger, just how close the country is to being led by a member of the Facebook generation – those of us currently under-35.

Not the next PM, but possibly the one after that, will probably be of an age that their youth has been perfectly preserved for all to see thanks to the joys of social media.

There is then a certain irony in the age of the whistleblower who exposed the Prism programme.

Ed Snowden, formerly of the CIA and futurely of a prison cell, is only 29. He’s from Generation Facebook, Generation Twitter.

From his Hong Kong refuge, he said that he leaked the information about Prism because he found the scale of the surveillance to be “horrifying”.

Mr Snowden may care about his privacy, but precious few of his contemporaries care less.