All but one of the five mooted Game Of Thrones spin-off series has been chucked over The Wall and left for dead, with the prequel series developed by George RR Martin and Kingsman writer Jane Goldman winning out.

"The reason we did multiple scripts, in the development process, [was that we knew] out of five we’d be lucky to get one we’re excited about," HBO Programming President Casey Bloys said at a Television Critics Association panel on Wednesday, adding that "there are no plans to make any others at this point".

The prequel will be a story "chronicling the world’s descent from the golden Age of Heroes into its darkest hour. And only one thing is for sure: from the horrifying secrets of Westeros’ history to the true origin of the White Walkers, the mysteries of the East to the Starks of legend... It’s not the story we think we know."

It had always been HBO's intention to take a few pitches and pit them against each other; a Mother Of Dragons Den, if you will. Other concepts by Pacific Rim's writer Max Borenstein, Game Of Thrones' Bryan Cogman, Mad Men scriptwriter Carly Wray and writer and director Bryan Helgeland have been shelved.

HBO's Senior VP Drama Francesca Orsi said at the INTV conference in March that we could expect "three, four, five spin-offs" set in the Game Of Thrones universe, and that it would be tantamount to "corporate malfeasance" not to continue the story in some way.

Orsi also indicated that the spin-off will have a traditionally huge Game Of Thrones-level budget. "We're going big," she said.

In other Thrones news, Bloys also revealed that the final season will air in the first half of next year. As previous seasons have generally come out around April, it's a fairly safe bet that it'll land then again.