David Tennant has described his failed effort to crack US TV as an ‘interesting learning curve’.

The former Doctor Who star had been hoping to make it big with a starring role in Rex Is Not Your Lawyer.

But after heading to Los Angeles, TV chiefs in the US did not commission a full series of the show following the pilot episode.

David told the Radio Times that he has still not been informed what went wrong. “These are enormous empires and you don’t hear anything, you just get told what to do.”

David, soon to be seen in BBC One drama Single Father, said the process was a ‘political minefield’.

“You have to be careful about what you say about what you knew, because everybody tells you things that they’re not supposed to and you’re not quite sure what’s true and what isn’t.

“It was a fantastic experience to have. I learnt a lot about how that network in television works and how I feel about that. It was a very interesting learning curve.”

However he said he is not regretting his decision to quit his role as the Time Lord, allowing new boy Matt Smith to take on the role.

“No, it felt just right, actually. It still does. It felt right to pass the baton on and for it to continue to thrive. It was just wonderful and it created many, many more opportunities than it closed down.

“I think my life is in a very different place and my career is in a very different place to what it was before I did Doctor Who and that is 90 per cent positive.”

The full interview is in the Radio Times on sale on Wednesday, 6 October.