Purpose: This paper aims to consider the practices and experiences of the new school-based mentors for Early Career Teachers (ECT's), emerging from the UK Government's new early career framework (ECF) policy (DfE, 2019a). The paper uses Lipsky's (2010) framing of professionals as "street level bureaucrats" to consider the extent to which the ECT mentors, as new policy actors, exercise professional discretion (Lipsky, 2010) in negotiating and aligning the new ECF policy with existing practice. Design/methodology/approach: To research the mentor's interpretation and enactment of the new ECF policy, semi structured interviews were undertaken with an initial sample of nine mentors and four induction tutors who were also mentors. Online semi structured interviews were held, lasting around 50 min. This method was largely pragmatic as the study started during a period when schools were still cautious of face-to-face visitors in terms of COVID-19. Although the benefits for the interviewer experiencing the culture and context in which the ECT mentor was situated were lost, offering online interviews was critical in securing mentors' time. Findings: Findings suggest a disconnect between the intentions of the policy and the reality of its enactment at a local level. The ECT mentors have limited professional discretion, but some are exercising this in relation to their own professional development and the training they are providing for their ECTs. Most of the mentors are adapting the ECT's professional development journey whilst mindful of the programme requirements. The degree to which the ECT mentors used professional discretion was linked and limited largely by their own levels of confidence and experience of mentoring, and to a lesser extent the culture of their schools. Research limitations/implications: The ECF policy represents an important step in acknowledging the need to professionally develop mentors for the work they undertake supporting beginning teachers. However, the time and the content of the mentor training have not been given sufficient attention and remains a hugely missed opportunity. It does not appear to be recognised by the government policy makers but more significantly and concerning in this research sample it is not being recognised sufficiently by those mentoring the ECTs themselves. Practical implications: There is an urgent need by the UK government and school leaders to understand the link between the quality of mentor preparation and the quality of the ECTs who will be entering the profession and influencing the quality of education in future years. More time and resourcing need to be focussed on the professional development of mentors enabling them to exercise professional discretion in increasingly sophisticated ways in relation to the implementation of the ECF policy. Originality/value: The ECF policy is the latest English government response to international concerns around the recruitment and retention of teachers. The policy mandates for a new policy actor: the ECT mentor, responsible for the support and professional development of beginning teachers. The nature of the mentor's role in relation to the policy is emerging and provides an interesting case study in the disconnect between the intentions of a policy and its initial enactment on the ground. The mentors may be viewed as street level bureaucrats exercising degrees of professional discretion as they interpret the policy in their own school context.