INMAT, a Multi-Academy-Trust of 11 primary academies in Northamptonshire, faced increasing costs (£328,000 in 2021/22) and inefficiencies with their decentralised supply teacher management. In response, INMAT’s CFO, Becci Denbigh, spearheaded the centralisation of their supply system using Teacher Booker’s innovative Supply Pool software. This strategic move aimed to streamline the supply process, enhance teacher quality, and ensure cost-effectiveness. The transition to Teacher Booker involved careful navigation through industry-specific challenges, with a focus on optimising staffing solutions, improving compliance and vetting processes, and easing system adoption for headteachers. The results were remarkable: INMAT booked 165 days of supply within 6 weeks and achieved £9,405 in agency fee savings in less than a term. This success story highlights the increased efficiency, reduced administrative burden, and strengthened trust identity that can be achieved through a tech-driven approach in education supply management.


INMAT is a group of 11 primary schools based in Northamptonshire. Historically, INMAT has relied upon outsourcing its supply needs to supply teacher agencies in the local area.

Historically the Trust did not have a Preferred Supplier or preferred agencies for its schools to work with and so had very little control over which agencies were used, what rates they charged and therefore minimal oversight on spending across the Trust or on an individual school level. Trust spending on supply staff has been increasing year on year, rising to £328,000 in 2021/22 from £295,000 from the previous year. Headteachers across the Trust were responsible for booking supply independently. This was a manual process which involved calling and emailing many different supply agencies and could take several hours each day.

The Project

Across the UK, on average quarter of a Trust’s total spend on agency supply staff covers the supply agency service fees (the other three quarters is the supply teachers’ wages). In INMAT’s case during 2021/22 this is estimated to be £82,000 in agency service fees. The trust engaged a wide range of agencies as suppliers and little central oversight of quality, value for money and spend.

Graph showing cost breakdown for supply for years 20/21 and 21/22 for INMAT

With a clear rising spend on agency staff Becci Denbigh, INMAT CFO, identified an opportunity to save money, improve oversight and standardise INMAT’s provision of supply staff across the Trust by opening a dedicated INMAT supply pool. 

Becci believed that by centralising the function of supply across the Trust they would realise significant outcomes including a reduction in agency spend, improved quality of supply teachers and improved consistency of supply work. 

Furthermore, with the increasing adoption of technology-led services in schools, Becci believed that a supply pool supported by a modern, digital booking system would also lead to other efficiencies. These would include time saving, reduced administration, reduced head teacher stress and ease of documentation storage and compliance sharing to ensure safeguarding requirements are always met.

Problems, Challenges and Hesitations

At the outset of the project several key challenges were identified:

Obtaining Staff: First and foremost was the question of how INMAT would be able to fill its supply pool and how many supply teachers/support staff they would need. Concurrent staffing shortages across the entire education sector, as well as agency dominance over the local supply chain, meant that there was some doubt as to whether it would be possible to identify and engage enough supply teachers/support staff in the local area to get the project off the ground. 

Dealing with Agencies: As almost all supply teachers in the local area were registered with supply teacher agencies, the Trust was worried that they might fall foul of supply teacher agency terms and conditions and incur significant costs by way of engagement fees.

Compliance and Vetting: The Trust did not have centralised capacity to be able to carry out the necessary compliance and vetting checks on supply staff who joined the INMAT supply pool, without which it would not be possible to utilise the supply pool. 

System Adoption & Deployment: There was some concern and doubt from headteachers about adopting a new system. While the headteachers agreed that having to pay agencies in order to fill supply bookings was not an ideal solution, they were used to resourcing staff this way and had a natural apprehension of adopting something new. 

Pay Rates & Payment Models: The Trust had very little information on what gross pay rates supply teachers in the local area were receiving from their agencies and were unsure of how to obtain this information, which they would need in order to ensure that they were offering a competitive gross pay rate and to be able to quantify the savings that they could make. Further to this the Trust was unsure of how payroll for staff in their supply pool would be handled, not having a system in place already for ad hoc workers.


After considering several options Becci decided that Teacher Booker’s Supply Pool software and associated wrap-around Managed Recruitment Services for candidate attraction, compliance and payroll provided the best, all-in-one solution to meet their needs and solve the identified challenges. Teacher Booker worked closely with the MAT central team, putting together a roadmap and industry experience to advise in key areas: 

Obtaining Staff: Teacher Booker worked with the INMAT central team to analyse their spend on supply staff and to estimate the number of supply teachers and support staff they would need based on their historical supply usage. 

It was determined that the Trust would need 20 supply teachers in their supply pool to be able to consistently meet the needs of their schools. The Trust first turned to its own staff body to identify potential supply teachers among current part-time workers and those looking for more flexible working. The Trust was able to source 40% of their supply pool from internal staff alone. The Trust was then guided to use its extended staff network to reach out to former INMAT employees and sources a further 30% of their supply pool from their own network.

The final 30% of workers was sourced with the help of word of mouth and through Teacher Booker’s marketing support.

Dealing with Agencies: Teacher Booker provided direct, industry specific guidance to enable INMAT to safely transfer agency supply teachers into their staff bank without breaching commercial terms or incurring potential engagement fees. 

Further guidance relating to the CCS Supply Teachers and Temporary Staffing (STaTS) Framework will enable the Trust to also transfer long term agency supply staff into the supply pool, further saving £1000s in agency fees. 

Compliance & Vetting: Teacher Booker’s Supply Pool software comes with a comprehensive compliance and vetting module which enabled INMAT to centrally store all compliance and vetting documents for workers in their supply pool, giving staff and member schools easy access to the vetting they required to meet safeguarding requirements. 

As INMAT did not have the capacity to be able to vet incoming supply teachers they engaged Teacher Booker’s compliance & vetting Managed Recruitment Services to rapidly process and clear supply teachers so that the project could successfully launch at the start of the academic year. 

System Adoption & Deployment: The cloud based, web-app nature of the software means that it can be easily and rapidly deployed. All necessary staff training was provided free of charge by Teacher Booker and despite some initial reservations, within 4 weeks of launch 10 out of 11 schools had successfully booked supply through the system. 

Pay Rates & Payment Models: Teacher Booker worked closely with the CFO to give them an in depth understanding of agency practices and to calculate local agency gross pay rates to ensure that their offering was the most competitive in the local area. 

Teacher Booker’s payroll service provided an easy, transparent and fair solution to the question of processing worker payments.

Results and Benefits (Quantitative & Qualitative)

The benefits of opening a supply pool became quickly evident. Within 6 weeks INMAT schools had booked 165 days of supply from their supply pool, saving £5798 had they booked these days through their previous main supply agency.

Feedback from staff operating between sites in the Trust was that being able to see the same supply teachers working across the Trust had created a greater sense of Trust identity and familiarity. By building their own network they felt safer and more confident, describing supply staff as “a real extension of our INMAT family”.

Headteachers reported quickly taking to the system. They noted that absences were often reported the evening before rather than the morning of, and that the system enables them to quickly resolve sudden absences in their own time rather than having to wait to contact an agency in the morning. Head teachers reported lower stress levels; being better able to forward plan their staffing needs led to a reduction in staffing related headaches and, crucially, saved time and resources.


The hypothesis that the MAT centralisation of supply services for a Trust through the creation of an internal supply pool would lead to benefits in efficiency, quality in supply teaching has been proven to be true. As has the theory that they would be able to realise significant savings on agency fees while maintaining high levels of school supply support: INMAT has now saved £9,120 in agency fees after less than full term’s operation.

Furthermore it is evident that the use of a dedicated technology solution to facilitate the creation of a supply pool makes the project far more likely to succeed.

Concerns that school users would have difficulties adopting such a new technology solution have been fully disproved. Head teachers are using the system on a near daily basis and have reported saving dozens of hours, they “find booking supply so much easier, quicker and a lot of their weekend stresses have been eliminated” and have now booked 160 days of supply from their internal supply pool. 

Finally, concerns around populating a supply pool in the context of a candidate shortage have also been disproved. With the rapid rate at which candidates joined the supply pool it is evident that supply teachers are looking for an alternative to traditional agency supply service and are in fact keen to work directly with school groups.

Client Testimonial: Becci Denbigh, CFO, INMAT

“In the short term we have been using Teacher Booker, my colleagues and I have really felt the benefits. Our Headteachers find booking supply so much easier, quicker and a lot of their weekend stresses around finding supply have been eliminated. We have found a way to establish not just a new bank of supply staff but a real extension of our INMAT family, with known, quality supply staff being readily available to work in our academies.

The support we have received from TeacherBooker in implementing this solution has been second to none and Ollie and Dani have felt like an extension of my central team. No ask is too much trouble and they always make time for you no matter how much notice is given. I can’t praise the team enough”

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