Wind back just 40 years ago and the thought of a world connected by a network of computers, capable of delivering media-rich information and entertainment at the touch of a button would have seemed the stuff of science fiction.

So, perhaps, just perhaps, the thought of technology being able to revive the dead in decades to come is not as ridiculous as it may first appear.

At least, that's the hope of thousands of people around the world, including some in Kent, who have pledged to pay tens of thousands of pounds - if not hundreds of thousands - to have their bodies (or in some cases just their heads) frozen when they die in the hope medical science will one day be able to revive them.

Welcome to the world of cryonics.

"The fundamental goal of cryonics is to give people a second chance at life," explains a spokesman for the Cryonics Institute in Michigan, in the US.

Founded in 1976 by Robert Ettinger, an academic dubbed 'the father of cryonics', the institute is a not-for-profit organisation which already has more than 100 people in their deep freeze facilities and in excess of 1,000 waiting to shuffle off this mortal coil and into one of their cryostasis chambers.

Worth noting is that its first 'customer', in 1977, was Rhea Ettinger - its founder's mother. His first and second wives are in there too, and he joined them when he died in 2011. If all goes to plan, their revival is going to make for some stellar reality TV.

Ettinger had penned, in 1962, The Prospect of Immortality - which outlined the basic premise of cryonics; namely that if the body can be frozen almost immediately at the point of death, medical science, in the future, could successfully revive the whole body, or at least just the brain, and bring it back to life.

"The process of cryopreservation," explains the Cryonics Institute, "involves cooling a legally-dead person to liquid nitrogen temperature where all physical decay essentially stops - with the goal of preserving tissues, organs and especially the brain with its associated memories and personality as perfectly as possible.

"A person held in this state is termed a 'cryopreserved patient', because we do not consider the legal definition of 'death' as a permanently irreversible state. We believe that the incredible advances being made today in biology, medicine, computers, nanotechnology and much more inevitably point to a future where advanced science will be able to revive these patients and restore them to health and even renewed youth.

"Essentially, the concept is to 'buy time' until technology catches up and is able to fully repair and restore the human body."

Adds Alcor, another one of the big players in this niche industry, based in Arizona: "The purpose of cryonics is to intercept and stop the dying process within the window of time that it may be reversible in the future.

"The first few minutes of clinical death are certainly reversible, even today. There are good reasons to believe that this window will extend further in the future. That is why cryonics is sometimes implemented even long after the heart stops. Cryonics is not a belief that the dead can be revived. Cryonics is a belief that no one is really dead until their mind is destroyed, and that low temperatures have the potential to prevent this destruction."

The ethical issues of such an action are broad and could fill many pages of this website.

Paul Sullivan is funeral director of Sullivan & Son in Dover. Offering the chance to be cryonically preserved is one of the options open to his customers.

He explains: "Since I opened my own business in 2007, I wanted to include all available options on my website to give people the chance of having it or at least thinking about it.

"I was rather intrigued (when I first heard about cryonics) but knew it would be a very rare request.

"I don't get regular enquiries about it and I think it’s a very niche option which actually appeals to very few."

And little wonder. Quite aside from the prospect of returning to a world where you know no-one, the costs of committing your body to future scientific breakthroughs is not only phenomenally expensive, but also presents some key issues for those friends and family left behind who, added to their sense of loss, have the issue of their loved one's body being flown halfway around the world and locked in a facility.

Yet all that notwithstanding, he has one client - a currently very much alive and kicking 41-year-old - on his books and ready to take a pricey punt on future revival.

"It all depends on whether you go budget or high end," explains Tim Gibson from Cryonics UK.

"Basically, for your budget service, you're probably looking at around £50,000. All in. If you go with high end, you would spend £250,000 easy."

Cryonics UK is a charity which aims to help facilitate the final wishes of those signing up for the cryonics process.

It is, in truth, a slightly odd organisation.

Tim Gibson, a trustee, has acquired his own ambulance which he has on standby in order to rush to the death-bed of anyone signed up to the service and start the not-for the-faint-of-heart process of body preservation.

Its job is to basically get the body ready not only for the freezing process for an unspecified amount of time, but to transport them to one of only a handful of facilities in the world which cater for the expensive gamble of possible immortality.

Currently there are sites in the US, Russia and China - and plans for more in Switzerland and Australia too. Cryonics UK has a deal in place with US firm Alcor.

But before we get into the actual process of preserving a 'just-died' body and shipping it around the world, just what do you get if you can stretch your budget?

"The main difference with the high end is you get the higher tech, you get a higher level of backup," says Mr Gibson. "Also, the most significant factor is you get a huge investment in long term care.

"So about 50% of that quarter of a million goes into long term care. Whereas if you go for the budget option, you're more exposed.”

One pictures the cheaper option being a big freezer in a Texas warehouse.

"It's basically an investment,” he adds, “the more you have, the safer you are.

"It's a myth that only wealthy people can afford it. There are plenty of people who just decide instead of buying a packet of fags every week, they're going to pay for life insurance."

And it's the life insurance pay-out which many rely on to pay for their 'storage' post mortem.

But, as undertaker Paul Sullivan explains, it's not just the price which can be the stumbling block.

"It is very expensive which reduces the market but personally I think the main issue is people's reluctance to choose it for themselves," he says. " This is for a variety of reasons other than its cost: Religious beliefs; not wanting to leave England; worrying about exactly what will happen to them if the storage facility was subject to any disaster or breakdown; disliking the idea of possibly coming back decades later to what kind of Earth and existence; and general cynicism and doubt that it could ever work.

"Personally, I don’t think making it cheaper would result in greater uptake - perhaps only greater cynicism."

And it's fair to say that while the scientific process of body preservation could work, trying to find anyone in the scientific sphere to wax lyrical on the subject is challenging - few, it seems, wish to discuss something which is mocked far more than it is applauded.

Although the likes of Alcor will quickly point you in the direction of an open letter signed by more than 60 scientists and ethicists, from around the world, endorsing the scientific basis of cryonics.

Cryonics UK's Tim Gibson, 50, is, perhaps not surprisingly, one of those signed up to be frozen when his time comes.

A landlord in addition to his work driving his second-hand ambulance for Cryonics UK (if student accommodation in Sheffield is what you’re after), he signed up to a life insurance policy to pay to have his head preserved when he dies (he's said he'd rather not come back with an 80-year-old's body so hopes scientific advances will allow for him to have a nice new young body fitted below the neck when he's eventually revived.

"I think one of the things that gets bigged up in the newspapers is people want to discuss all the potential pitfalls of cryonics," he says.

"Yes, there are potential pitfalls and there is potential for it not to work and all that kind of stuff. But your typical person who signs up will be aware of all that, and they'll just go, yeah, I'm going to roll the dice."

So just what happens as you approach your final farewell to this world and you have signed up to "roll the dice" on the cryonics craps table?

Well, ideally, before Mr Gibson and his hired team of medics arrives, they'll get a call warning them the end is nigh for the soon-to-be-frozen customer.

"We get the call and we'll have to make arrangements with the hospital, care home or GP, depending where they are," he explains.

"We'll have to speak to the coroner, to see if they have any interest in it, but if they haven't, then it's a pretty straightforward process. Obviously if someone’s been told they are dying then there’s little to have to investigate.

"We also have to brief the family and get them involved because the people you really rely on for cryonics is the doctor and the family. We always tell people you must tell them what your plans are because otherwise you're making it 10 times harder for yourself when the time comes.

"So when we know they may be going in 24 to 48 hours you assemble the team and await the call.

"Once you get your cardiac arrest, you go in and check all vital signs and the death is pronounced.

"You put your patient on to cardiac support on a ventilator. So effectively, you're taking them in the same way you would someone who has a heart attack in the street and you stick them onto the support mechanisms. You're doing the same job, more or less, but you don't want to wake them up or revive them. And you're not likely to because that's the reason they've died because they're so sort of functionally messed up they won't stay alive naturally anyway.

"So they're relying on your cardiac support for circulation, ventilation, oxygen supply, then because effectively, the brain shuts down at this point, it's got its oxygen supply, so it doesn't deteriorate.

"But it doesn't control the body either, because it's not actually switched on if you like. So you've got to have a whole cocktail of drugs that basically stabilise the biochemistry.

"And all this is going on while they're in an ice bath, because you've got to cool them down. They've got to come down from a normal body temperature of 37 degrees to about 10-20 degrees.

"That gives you an opportunity to do surgery.

"So essentially we're creating a window where the body can survive without the need for oxygen."

At that point the body is moved to a suitable location for the next phase. And if you're eating, you may wish to pause for the next part.

Explains Mr Gibson: "The surgery involves basically tapping into the vessels in the neck and connecting in a pump system which pumps blood out and preservation fluid into the head to preserve the brain tissue. And that in itself is freezing cold. So it drops the temperature pretty fast.

"Those which bring it down below zero effectively contain a form of anti-freeze.

"The idea is because of that, when we drop the patient through at minus-80, they don't actually freeze up."

If you've splashed out for the full body service then all good. If not, let's just say it's at this stage you lose your head. Literally. Which, given you're dead, is not going to bother you. Just pray the medical team around you don't lose theirs, metaphorically.

Once enough of the preservation fluid is pumped in then the body (or head) is put into dry ice which will take the temperature down from around zero to about minus-70 over the course of several days. And then they're ready to be shipped.

"The surgery involves basically tapping into the vessels in the neck and connecting in a pump system which pumps blood out and preservation fluid into the head to preserve the brain tissue..."

Which means the Cryonics UK team get to work with the all-important paperwork.

Adds Mr Gibson: "You need to get the coroner's authorisation to leave the country and you've got to get permission to get into the US or Russia. So you've got to go to their embassy and get all the right paperwork and book the flights.

"You've got to have your infection-free certificate, basically to show that they're being appropriately treated and that they're not a biohazard."

Checking in your bags at an airport can often be a drawn-out process. Imagine the complexities of checking in a body or severed head.

"Cryonics is 50 odd years-old now," says Mr Gibson, who frequently finds himself doing the late-night run to the airport with his 'cargo'. "They've all heard of it before. Last time I went to the airport, when I offloaded the shipping case the lady on the desk said: 'I saw the symbol, I've done this before'. So it's not new to many people. It's not common, but it is something that sticks in people's heads, so they remember it."

And off they go. By air cargo, to the storage facility of their choice.

"The obvious question people used to ask," says Mr Gibson, a man clearly well used to speaking to those who doubt the wisdom of the cryonics process, "is what happens if the storage fails?

"Well the chances are pretty slim because it's not power sensitive. It's just a big vacuum flask with liquid nitrogen in it. If it leaks, you will notice and they'll have low level sensors on them so they will get an alarm. If the truck gets lost en route to the facility, it's not a problem because the container they are shipped in doesn't need topping up for two months."

But, it's fair to say, it's not everyone's cup of tea.

In fact, Cryonics UK have only handled 20 cases in the last 10 years or so. The service is also proving popular from those wanting their pets preserved. Although little Tiddles may be in for a rude awakening when finally revived to discover his owner bit the dust some decades ago.

However, Cryonics UK says interest is increasing rapidly, with Covid heightening people's sense of their own mortality resulting in a surge of recent enquiries.

Not that funeral director Paul Sullivan is convinced.

"Of course I've thought about it," he admits. "But it is not what I want. However, I am glad to offer the option because that’s what life’s about isn’t it – personal choice and belief."

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