Andrew Vine: While you’re watching TV, is it listening to you?

Or is there a threat to your banking details or simply peace of mind lurking in the kitchen, or the hallway, ever-vigilant and tireless in collecting information you would never normally share with a third party?

It sounds far-fetched, the stuff of science fiction, but the chilling notion that increasing numbers of us are under a form of surveillance in our own homes appears to be coming true.

Last week brought two warnings that a new generation of internet-enabled household appliances is putting our privacy at risk.

So-called smart televisions that can be programmed to change channels in response to a voice command have already come under the spotlight as one major manufacturer warned its customers not to discuss personal or sensitive information when the set may be “listening”.

Now it has emerged that living room conversations captured by televisions made by a second leading manufacturer could be handed over to a disturbingly wide range of third parties, among them debt collectors and marketing firms from around the world.

Such a degree of electronic snooping would be alarming enough, but it’s not just televisions that are becoming capable of tracking what we’re up to.

Fridges, washing machines, central heating thermostats and even toasters are increasingly becoming internet-enabled, with the ability to adjust their functions to save power automatically, or be controlled remotely from smartphones.

So far, so convenient. Except an internet security firm has revealed that last year 750,000 phishing and spam messages were sent via 100,000 household devices like this that had been commandeered by hackers.

This really is scary stuff. Anybody with a home computer – and that’s an overwhelming majority of us – knows it is essential to have security software in place to stay protected against threats.

But this new wave of intrusions into our lives is altogether more insidious. Sitting at the computer and taking the conscious decision to connect to others is one thing. Having household appliances connecting themselves – and potentially being vulnerable to hijack – is entirely another.

There is something extremely sinister about this, not least because we probably don’t realise it is happening and are helpless to do much about it.

In our own homes, we let our guard down in a manner we would never do in public or in the workplace.

This is where our most frank, or sensitive, conversations take place because we feel we have shut the world out. Family issues, worries over work or money, hopes or concerns about the future – all these are aired in living rooms where the television may be burbling away in the background.

The idea that somebody, somewhere, could potentially be listening is an invasion of the sanctity of our homes.

We can, of course, shut out the listeners by sticking to using the remote control to change channels and not enabling our new televisions to recognise our voices, but even so there remains the nagging worry that we have brought an electronic snooper home from the shop.

Perhaps a time is approaching when people turn the television off, just in case, if a conversation strays into serious territory. If so, that in itself would be a breach of the sense of security we all deserve within our own four walls.

Most of us are already the victims of electronic snooping. Bank or supermarket loyalty cards paint a picture of our spending and shopping habits, and our online movements sketch in our interests or hobbies.

All of this produces snapshots of our lives that can be used to market products or services more directly and accurately than ever before, which is, in one sense, useful to us.

But the potential to monitor us when we’re not shopping or online, instead simply relaxing at home is where it begins to feel like the Big Brother of George Orwell’s Nineteen Eighty-Four has become reality and is peering into every nook and cranny of our lives.

The number of homes harbouring technology with the potential for surveillance will only grow, however uncomfortable householders may be about that. Just as black-and-white sets were supplanted by colour, and then flat-screens replaced bulky ones, so the time will come when every new television sold is likely to be capable of transmitting information about what we watch and even what we say.

And all the while, hackers will be probing for chinks in the armour of state-of-the-art household appliances as more and more of them become connected.

A line has been crossed without many people realising it, and as a result our privacy will never be quite the same again.