Abstract Aim Colorectal cancer (CRC) is the 4th most common cancer in the U.K. contributing to 10% of cancer-related fatalities. Despite clear NICE referral guidelines, there are various patient-, clinician- and system-related delays in referrals to the lower gastrointestinal (LGI) services. Our article investigated clinician-associated biases that govern the timeliness of referral to the LGI services. Method Our article is a narrative review. We searched Embase and Ovid Medline databases using a range of terms. Results yielded 36 articles relevant to our topic. Results GP referrals make up 44%-69% of suspected CRC referrals. Yet, national data highlights that emergency presentations range from 14%-30% nationwide, indicating missed opportunity in the primary care setting. Cognitive bias was commonly seen and included GP’s poor familiarity with referral criteria and failure to recognise red flags. Patient cultural and demographical biases played a significant role in decision-making often leading to misappraisal, with the patient’s age being the most common factor. Younger patients were less commonly referred onto the 2-week-wait (2ww) pathway, and faced an average delay in diagnosis of a month with 1.4 times more visits to care providers. In addition, information and communication biases were a recurring theme in the literature which discussed the effects of inadequate histories and physical examinations on missed diagnosis and delayed referrals. Conclusions Unintentional bias delays CRC referrals resulting in a substantial proportion of patients presenting as an emergency with advanced stage cancer that has poorer outcome. We need to increase awareness of these biases and find ways to negate their effects in clinical decision-making.