Belle is back and sexier than ever in the fourth and final provocative series of the smash hit TV series Secret Diary of a Call Girl.

In Series 4, Belle (Billie Piper: Dr Who) takes on a new relationship with best friend Ben (Iddo Goldberg: Defiance) and the new role of managing Stephanie's escort business. The stakes have never been higher for Belle - accepting Ben's offer of a lasting relationship means that Belle has a real chance of happiness; but Ben is her one true friend and if she messes up, she'll lose him forever.

With Stephanie in prison for her dodgy finances, Belle finds herself being a Madam, whilst also becoming the unlikely guardian of Stephanie's innocent 19-year-old daughter, Poppy (Lily James).

Belle successfully starts to manage other girls - including the feisty and uncontrollable Dominatrix Charlotte (Gemma Chan: Submarine) while still taking on an array of new clients with bizarre requirements. But as Belle excels in her professional life, her personal life starts to fall apart

Will she give up ‘Belle' for Ben and commit to being just ‘Hannah' or will she cut all ties and throw herself into the world of a high-class escort forever? Find out all in Secret Diary of a Call Girl's saucy and unmissable climax.