ESOS NEWSLETTER – OCTOBER 2025 - One Login
This issue of the ESOS Newsletter from the Environment Agency shares information on GOV.UK One Login rollout to MESOS and submission of the Progress Update 1.
GOV.UK One Login rollout to MESOS
The Environment Agency (EA) introduced a new way to sign in to the Manage your Energy Savings Opportunity Scheme Reporting system (MESOS), using GOV.UK One Login. This is the new secure way to access government services and will be rolled out across more services in the future.
A trial of the new sign-in process has already taken place with a proportion of MESOS users. Due to the success of the trial the EA is now notifying all MESOS users that they can now begin to connect their MESOS accounts to One Login – please go to the MESOS sign in page and refer to the steps at Annex A – One Login Guidance below.
Benefits of GOV.UK One Login
GOV.UK One Login provides:
- access to multiple government services with one set of sign-in details
- enhanced security with two-factor authentication
- the option to use GOV.UK One Login to verify your identity for Companies House
In the future, GOV.UK One Login will replace all other ways to sign in to services on GOV.UK, including Government Gateway.
Progress update 1
You are reminded that the deadline for the initial progress update (PU1), which is required to be submitted following notification of the action plan, is 5 December 2025.
All ESOS participants are required to submit a PU1, regardless of whether or not their submitted action plan included proposals on any energy efficiency measures. The PU1 seeks updates on any measures in the action plan, and information about any measures implemented which were not originally proposed in the action plan.
To assist you to complete the PU1, you may wish to use the PU template provided under the Progress Update guidance in MESOS, the 'Phase 3 How to Comply with the Energy Savings Opportunity Scheme’ guidance document and the Q&A previously circulated in the ESOS Newsletter May 2025 Issue 36.
Publication of Phase 3 action plan data
The Phase 3 action plan dataset, which has now been published, contains data from action plans submitted by participants by 5 June 2025 following the submission of their Phase 3 notifications of compliance (NOCs).
The data includes:
- the name of the organisation
- measures that ESOS participants propose to implement by 5 December 2027 (the end of the Phase 4 compliance period)
- dates by which the measures are proposed to be implemented (month/year)
- the total energy savings estimated to be achieved from implementing each measure
- the total energy savings estimated for each measure broken down by organisational purpose
- estimation methods used to calculate energy savings
- any context to proposed measures (where provided)
Annex A – One Login Guidance
Connecting GOV.UK One Login to your MESOS account
- Select ‘Start now’. You’ll be taken to GOV.UK One Login, where you can create a GOV.UK One Login if you do not already have one.
- GOV.UK One Login will return you to the MESOS service.
- Choose to connect your existing MESOS account to your GOV.UK One Login.
- Confirm your identity using your MESOS sign in details.
Once connected, you’ll use GOV.UK One Login to access your MESOS account from then on.
If you have forgotten your MESOS sign in details
Resetting either a password or a two-factor authenticator app (2FA) for your MESOS account
- During the process of connecting GOV.UK One Login to your MESOS account, you will be asked to enter your email address and confirm your identity using your existing MESOS password and 2FA.
- If you need to reset your password, use the ‘I have forgotten or want to change my password’ link.
- If you need to reset your authenticator app, use the ‘I have lost access to my authenticator app’ link.
- You will receive an email which will allow you to reset either your password or your 2FA app. Please ensure that Junk/Spam folders are also checked for these emails.
- If you still cannot sign in after following these steps, contact the ESOS IT helpdesk.
Resetting both the password and two-factor authenticator app (2FA) for your MESOS account
- You must first reset one of the details, either your password or the 2FA app.
- When you are asked for the other detail, select ‘I have forgotten my password and lost access to my authenticator app’.
- You will be taken to the ‘Reset MESOS account password and authenticator app’ form.
- Enter your name and the email address you use to sign in to MESOS.
- Submit the form. You’ll get an email confirming that your request has been received. Once your request has been processed, you’ll get another email with a link and instructions on how to reset your MESOS sign in details. Please ensure that Junk/Spam folders are also checked for these emails.
Contact the Environment Agency
For any IT specific queries relating to the MESOS Reporting System, please contact the EA's ESOS IT helpdesk.
If you have any queries relating to ESOS or if there is anything specific you would like to see in future ESOS newsletters, please consult the ESOS Guidance in the first instance or email the EA's ESOS Technical Helpdesk.