Introduction In the United Kingdom, work-based assessments (WBAs) including procedure-based assessments (PBAs), case-based discussions (CBDs), clinical evaluation exercises (CEXs), and direct observation of procedural skills (DOPS) have been used in Higher General Surgical Training Program (HGSTP) since the introduction of Modernising Medical Careers. Although the Intercollegiate Surgical Curriculum Project states that they should be used for the formative development of trainees using feedback and reflection, there is no study to look at the perception of their usefulness and barriers in using them, particularly in HGSTP. The aim of this study is to investigate trainer's and trainee's perception of their usefulness, barriers in using them, and way forward for their improvement in HGSTP. Methods This was a mixed method study. In phase I, after ethics committee approval, an online survey was sent to 83 trainers and 104 trainees, with a response rate of 33 and 37%, respectively, using Online Surveys (formerly Bristol Online Survey) from July 2018 to December 2018. After analysis of this result, in phase II, semistructured interviews were conducted with five trainees and five trainers who had volunteered to take part from phase I. Thematic analysis was performed to develop overarching themes. Results For professional formative development, 15% of the trainers and 53% of the trainees felt that WBAs had a low value. Among 4 WBAs—CEX, CBD, PBA, and DOPS—PBA was thought to be the most useful WBA by 52% trainers and 74% trainees. More trainers than trainees felt that it was being used as a formative tool (33 vs. 16%). The total number of WBAs thought to be required was between 20 and 40 per year, with 46% of the trainers and 53% of the trainees preferring these numbers.The thematic analysis generated four themes with subthemes in each: theme 1, “factors affecting usefulness,” including the mode of validation, trainer/trainee engagement, and time spent in validating; theme 2, “doubt on utility” due to doubt on validity and being used as a tick-box exercise; theme 3, “pitfalls/difficulties” due to lack of time to validate, late validation, e-mail rather than face-to-face validation, trainer and trainee behavior, variability in feedback given, and emphasis on number than quality; and theme 4, “improvement strategies.” Conclusions The WBAs are not being used in a way they are supposed to be used. The perception of educational impact (Kirkpatrick levels 1 and 2) by trainers was more optimistic than by trainees. Improvements can be made by giving/finding more time, trainer training, more face-to-face validation, and better trainer trainee interactions.