Not a problem.
Keep the TX in a carry-on bag, so you have access to it once the plane is in the air. I've carried mine in my pocket, and going through security at the airport is the only hitch. Once you get to security, pull it out, place it in the basket for scanning, then pick it up again on the other side. If you keep it in a carry-on bag, you'll avoid any overly eager security person who may want you to show it to them, and make sure it's really a computer, etc.
The flight attendants aboard the aircraft will tell everybody when you can pull out your cellphones, computers, PDAs, etc. You can use it the whole time.. except during take-off and landing.
Bring along your A.C. adapter and U.K. power plug (my TX came with a bag of overseas adapter plugs). The largest one in the bag will be the one for U.K.