Originally Posted by HarryT
Yes, I know the later stories are still under US copyright. What I actually meant was that Anthony Horowitz is a British author, and hence doesn't need anyone's permission to write a Sherlock Holmes story, because all the Holmes stories are in the UK public domain
. Hence my question about what permission he would require.
He needs* permission if his book is going to be published in the US, which is several times the size of the UK market.
*or maybe not. We should find out in a few months/years. Hopefully before the US copyright runs out.