I am planning to travel to the caribbean via the US and will have a stop over in Houston for about 8hours. Does anyone know if I have to fill out any forms?
I've read about the US visa waiver for Uk nationals, so with my UK passport and PR card, I think I should be okay, but then I also read about an ESTA form and not sure if it applies to me.
Anyhelp is greatly appreciated.
Cheers!

You will need ESTA.

Even with a visa to the US you should fill out the ESTA. I mistakenly trusted the information from the consulate that I would not need an ESTA once my visa started then got held back on re-entry one time because my ESTA had expired. Almost missed my next flight.

Eligible nationals or citizens of countries that participate in the Visa Waiver Program require either a travel authorization or a visa to transit the United States. If a traveler is only planning to transit through the United States en route to another country, when he or she completes the travel authorization application in ESTA, the traveler should enter the words "In Transit" and his or her final destination location in the address lines in the Address While In The United States field on the application.

Cheers all. Completed the ESTA form and have authorisation.