I asked Think or Swim whether I would be able to set up an account. I am based in the UK. I got this reply from them....
Hello,
After assessing global requirements for doing international business, thinkorswim by TD Ameritrade has decided that we will no longer open new accounts in certain international jurisdictions. The UK is affiliated with at least one of these jurisdictions in which we will no longer provide brokerage services. As a result, we will not be able to open your account nor allow a demo account.
....can anyone shed any light on which jurisdictions they are referring to, and why???????