Privacy
Last updated: 18th August 2026
Who we are
Tertium Research Limited is the data controller for personal data collected through www.reasonably-accountable.com.
- Company number: 17289525
- Registered office: 53 Hall Drive, London SE26 6XL, United Kingdom
- ICO registration number: ZC225849
- Email: chris@tertium-research.com
What we collect
If you subscribe or become a member: your email address; your name, if you give one; your membership tier and status; and, for paid members, billing information held by Stripe. We do not see or store your full card details.
If you receive our emails: whether an email was opened, and whether links in it were clicked, together with limited technical data about the device used.
If you visit the site: your IP address, browser and device type, referring page, and the pages you view. Sign-in for members is by emailed link or code, which involves a short-lived token associated with your address.
If you email us: whatever you choose to tell us, and the message itself.
Why we use it, and on what basis
| Purpose | Lawful basis |
|---|---|
| Providing your membership and giving access to content | Performance of a contract with you |
| Taking payment and keeping accounting records | Contract; legal obligation |
| Sending the newsletter you signed up for | Consent, which you may withdraw at any time |
| Measuring how posts and emails perform, in aggregate | Legitimate interests: understanding what is worth writing |
| Keeping the site secure and preventing fraud | Legitimate interests: protecting the site and our members |
| Responding to your correspondence | Legitimate interests: replying to people who write to us |
| Meeting tax, accounting, and regulatory obligations | Legal obligation |
Where we rely on legitimate interests, we have considered whether our interest is
outweighed by your rights, and concluded it is not. You may object: see below.
Who we share it with
We use the following processors and service providers:
- Ghost (The Ghost Foundation): publishing platform and membership infrastructure
- Mailgun: delivery of newsletter emails
- Stripe: payment processing (Stripe acts as an independent controller for some
purposes, under its own privacy policy) - Our accountants and professional advisers, where necessary
We may disclose personal data where required by law. We do not sell personal data, and we do not share it for anyone else's marketing.
Transfers outside the UK
Some of these providers process data outside the UK, including in the United States. Where that happens, transfers are made under the UK International Data Transfer Agreement, the UK Addendum to the EU Standard Contractual Clauses, or another lawful transfer mechanism.
How long we keep it
Member and subscriber records are kept for as long as your membership or subscription is active, and for two years afterwards in case you return. Records required for tax and accounting are kept for six years after the end of the relevant financial year. Correspondence is kept for two years. Aggregate statistics that no longer identify you may be kept indefinitely.
Cookies
We use cookies that are strictly necessary to operate the site: keeping you signed in as a member and, on paid pages, supporting Stripe's fraud prevention. These do not require your consent. If we use any analytics or other non-essential cookies, we will ask for your consent first, and you can change your choice at any time.
Your rights
You have the right to ask us for a copy of the personal data we hold about you; to have inaccurate data corrected; to have data erased in certain circumstances; to restrict or object to processing; to receive data you gave us in a portable format; and to withdraw consent to marketing at any time, which you can do using the unsubscribe link in any email or by writing to us.
Exercising these rights is free, and we will respond within one month. Email chris@tertium-research.com.
If you are unhappy with how we have handled your data, you can complain to the Information Commissioner's Office at ico.org.uk, or on 0303 123 1113. We would rather you came to us first, but that is your choice, not a condition.
Changes
We will post any changes to this notice here and update the date above. Where a change is material, we will tell members by email.