Understanding possible points of EPS system failure

Published on: 16th July 2015 | Updated on: 15th March 2022

Using EPS needs many components and it’s useful to be able to determine which components may have failed if EPS will not run properly for you.

An EPS prescription travels from the GP system, via the central ‘NHS Spine’ to the pharmacy PMR system back to the NHS Spine and eventually ends up at the Pricing Authority for pricing. Some of the areas where the system could fail include:

EPS - components of service

  1. The pharmacy system is the component that resides within the pharmacy and is used on a daily basis to aid in the dispensing process (i.e. the PMR, printer, scanner and smartcard reader).
  1. The network connection connects your pharmacy to the internet, and ‘aggregators’ connect pharmacies to the N3 (NHS) network. Most system suppliers will arrange connectivity.
  1. Message handlers: Most system suppliers use a central ‘message handler’ to send or receive prescription messages to/from the Spine. Each system supplier is responsible for their message handling method.
  1. The N3 network is the NHS’s internal network and allows organisations such as pharmacies to connect to Spine.
  1. TMS (Transactional Messaging Service) is the Spine’s equivalent of a postman and is responsible for delivering messages to and from the individual Spine components and the prescribing and pharmacy systems.
  1. The Electronic Prescription Service deals with incoming and outgoing electronic prescription messages.
  1. The Identity Agent checks the user has relevant authority to connect to the Spine and informs the prescribing or dispensing system of the activities the user has been sponsored to carry out. The prescribing or dispensing system then uses this information to allow the user to carry out those tasks
  1. Personal Demographics Service (PDS) is the electronic equivalent of the phone book. It contains the NHS number, name, address etc. (and any nominations) of each patient in England registered with an NHS number.
  1. NHS Choices hold the details of which pharmacies are EPS Release 2 enabled. It is essential that the information held on NHS Choices, including the pharmacy’s current trading name and postcode is up-to-date.
  1. Pricing Authority: When an electronic prescription claim notification is submitted to the Spine, the message is forwarded to the Pricing Authority so that the information can be used for reimbursement.
Frequently asked questions

Q. What measures have been taken to ensure EPS and Spine resilience?

The Spine is held over two, tier three rated data centres. The Spine servers have live failover capability so if the server in one data centre were to fail, the service would be transferred to the other data centre. The Spine is also protected as part of the country’s  ‘critical national infrastructure’, in the same way that other services essential to the running of the country, such as energy, are given special protection. As EPS deploys, the Spine’s disaster recovery capability is being regularly tested. In May 2012, a Disaster Recovery exercise was held to test to ensure that if there was ever a failure in one data centre, pharmacies could continue to access the service to create and retrieve prescriptions electronically. The exercise commenced at shortly before 10pm on a Saturday and involved forcing the server to switch off. The backup server took over and was available to prescribers and dispensers within 15 minutes. The data was checked and the server switched back on in the early hours of Sunday morning, which again went as designed with only a 15 minute service outage.

Further information and related resources

Read more at:

If you have queries on this webpage or you require more information please contact it@cpe.org.uk.



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