In Series 2’s “Party”, Trudy is the Swindon employee celebrating a birthday.
Trudy is one of the employees introduced from Wernham Hogg’s Swindon branch when the two offices are brought together. Her birthday provides the occasion for an office celebration, complete with cake and presents. The event quickly becomes awkward because David Brent cannot resist turning ordinary workplace moments into opportunities for jokes and attention-seeking.
The episode also uses Trudy’s party to highlight the contrast between the Swindon newcomers and the established Slough staff. Trudy is played by Rachel Isaac, while other Swindon employees introduced around this storyline include Brenda, Oliver and Rachel. That makes the names in the answer choices easy to confuse, but Brenda and Rachel are separate characters, not the birthday employee.
“Party” is the third episode of Series 2 and originally aired in 2002. Its birthday subplot sits alongside David’s attempts to impress consultants and Tim’s increasingly complicated interactions with the Swindon group.