They have been held in Santa Ana Jail, California, for the last seven months and are believed to be the first UK citizens to be convicted of publishing racist material online.
They claimed they should be acquitted because the articles were posted on a server registered in the US beyond the reach of UK law.
Lawyers in the UK had expected Sheppard and Whittle to lodge an appeal if the decision went against them, but it is now believed the pair have decided to return to Yorkshire to be sentenced.
In a letter to supporters, published on the British People’s Party website, they wrote: “We were thinking of appealing
and sticking it out, but really this place is replete with people hanging on hoping for a miracle that’s never going to happen, and we don’t want to join them…
“Better we think to go back to England, face the music and get it over with.”