Hi Guilliver,
I asked one of my colleagues about this and she has forwarded me an alert that has been issued by ABTA - please see the following;
"As you may be aware, various media streams are reporting that Thailand will be introducing a Tourist Tax from January 2014.
We have been in communication with the Tourism Authority of Thailand today to confirm details, and they have advised that whilst the Ministry of Health and the Ministry of Tourism & Sport are considering this idea along with other options, a bill is not yet approved and is still to be passed by the government.
The Tourism Authority of Thailand wish to stress that whilst a tourist tax will not be implemented in January 2014, it is possible that in the future this may be introduced but they will keep us fully informed of any developments, if this occurs."
Kindest regards,
Julia