This cross-sectional survey examines the key barriers to expanding medical training posts across NHS Trusts in England, as identified by directors of medical education. This is currently a pressing national matter given the ongoing dispute between the BMA and the UK government, which includes the issue of training bottlenecks. The overwhelming consensus is that funding constraints is the most significant barrier, with other factors identified including limited educator capacity and inadequate educational facilities. Concerns were also raised regarding the ability to meet curricular and rotational requirements, particularly for higher specialty trainees. This survey also highlights disparities between different NHS Trusts and different specialties, which must be addressed on a local and regional level, respectively. These findings, which outline the necessary considerations for expanding the medical workforce, can inform the appropriate allocation of funding and resources. This survey invites further research on the economic impact of increasing trainee numbers to address the predominant issue of funding.