Image caption Louise Voss and Mark Edwards failed to get a conventional publishing deal for their two thrillers

As American John Locke becomes the first self-published writer to sell a million Kindle electronic books, the first "indie authors" to top the UK e-books chart explain their success.

Fed up that your latest masterpiece has failed to make it out of the literary agents' "slush piles" of unread manuscripts?

Self-publishing - paying a printer to run off a few hundred copies - has long been available as a last resort to frustrated amateur authors.

But it does not come cheap, and the chances of having a hit are virtually non-existent - it's with good reason that the practice is known as "vanity publishing".

Help appears to be at hand in the form of websites on which writers can publish their novels and sell them as e-books for electronic readers such as the Kindle.

On the face of it, the rise of such technology has the potential to democratise the publishing process.

British authors Louise Voss and Mark Edwards gave up on their dream of writing a bestseller years ago when their two finished thrillers failed to attract the attention of publishers.

Image caption Voss and Edwards take 35% of the sale price of their e-books

But when Edwards, who is the marketing director of a student finance website, bought an e-book reader last autumn and heard about Amazon's free direct publication system, he sensed a second chance.

Their second co-written novel, Catch Your Death - the tale of "a killer virus" and "a race to save the world" - is currently number one in the company's e-books bestsellers chart ahead of works by Stieg Larsson, John Grisham and Michael McIntyre.

It follows the success in the chart of their first novel, Killing Cupid, also still in the top 10.

"Its extraordinary and really unexpected," says Voss, a concert organiser at Kingston University.

"We did a lot of work and we worked hard to promote them but I don't think either of us thought in our wildest dreams that we'd be number one for two weeks and have two books in the top 10."

'Sales doubled'

Apart from their material, the key to success has been learning how best to market their material, including "piggy-backing" on the success of other similar e-books, as well as cross-promoting within their own two novels.

I was published a few years ago. I had a publishing deal and one of the things that was very distressing was how out of your own hands your destiny is Louise Voss, Author

"We rewrote the blurb for Killing Cupid to try to make it a lot more commercial and straightforward and within an hour sales doubled," she says.

"I was published a few years ago. I had a publishing deal and one of the things that was very distressing was how out of your own hands your destiny is."

Promotion methods for e-books were "very specific" and "in another six months or so, the publishers will have caught up with how to market books and get them up there and keep them up there", she added.

Voss and Edwards' two e-books have achieved combined sales of more than 30,000, with Catch Your Death now selling an average of 1,000 copies a day and Killing Cupid 500.

US contemporary crime writer Locke, who has enjoyed huge success with his Donovan Creed series, boasts on his website that "every seven seconds, 24 hours a day, a John Locke novel is downloaded somewhere in the world".

Locke, who has become only the eighth member of the "Kindle million club" - alongside authors including Stieg Larsson, James Patterson, Nora Roberts - charges 99 cents for his e-books.

He has said he started with this pricing system as a "loss leader" to entice readers into buying his more expensive titles.

Image caption Locke has also written a non-fiction title, How I Sold 1m E-books in Five Months

But "my loss lead became my biggest earner", he says.

Independent authors who sell their e-books for less than $2.99 (£1.84) receive 35% of that figure, taking 70% for books selling for above that price threshold.

These terms are far more generous than the cut taken by authors in conventional publishing.

Voss says she and Edwards priced low - Catch Your Death is on sale for 95p - "because we're not known authors" but always intended to raise the price to £1.99 "if the momentum got going".

But the duo - who as of last week have an agent working on securing a conventional publishing deal - now have no intention of changing the price.

"We're superstitious and, now that it's number one, we don't want to mess with it in case it suddenly drops out of the chart."