The present study is devoted to the quantitative characterisation of the interlayer bonding in unidirectional carbon fibre reinforced thermoplastic laminates produced by automated tape placement with in-situ consolidation (ATPisc). Two different manufacturing protocols were applied to produce the laminates that were further characterised using the quasi-static mode I double cantilever beam (DCB) test. Regardless of the manufacturing approach, the laminates exhibited multiple cracking accompanied by fibre bridging during testing, which affected the main mid-plane crack propagation. This effect was examined by comparing the crack length visually measured during testing with both the crack length back-calculated from the compliance and the crack length calculated using the flexural modulus and the compliance. In addition, the investigation of the evolution of the effective flexural modulus E₁ and the damage parameter φ throughout testing was performed for a better understanding of the damage accumulation in the specimens.