Ben Kaplan was an aspiring freelance journalist who was in a relationship with Jo Portman and ultimately got wrapped up in Section D's affairs after sleeping with Jo; having doing so while trying to expose what was going on with MI5 and Section D's activities in stopping terrorism.
Shortly after, during a hostage crisis where three important diplomats are held hostage, along with their audience, Ben helped Adam Carter and Ros Myers free the hostages. Ben was offered a position on the team by Adam, but refused. Later, following the death of Zafar Younis, Harry successfully recruited Ben after discovering he was extremely resourceful and had the making of a good MI5 officer, and so Ben replaced Zaf's place on the team, serving with them in the field on many important operations. When Harry was accused of being a FSB mole who was passing secrets from MI5 regarding "Operation Sugar Horse", Lucas North went to Russia to obtain proof of Harry's innocence and expose the real mole, Ben did the same in MI5's paper archive. At the same time, Lucas and Harry found out Connie James was the real mole, Ben found a form in the paper archive proving Connie was the mole, but Connie herself appeared in the archive to assist Ben in finding the form.
When Connie saw Ben put the form into his pocket, and to prevent Ben from leaving the archive to warn Ros and the rest of the team, Connie used a bladed garrotte wire, hidden in her bra, to slice his throat, and took the form from his pocket and left, leaving Ben to die in a puddle of his own blood. Ben's dead body was later found by the team. Connie was arrested by Ros as she tried to escape, and, on the now-exonerated Harry's recommendation; Home Secretary Nicholas Blake MP posthumously awarded Ben a Distinguished Service Order; for all of his contributions to MI5 and Britain.