March 2026

For the last two years, I have been learning a lot of new words. Some of these I have learned by choice, as in my German lessons, or my pathetic attempts to learn how to transliterate 17^th century Scottish manuscripts. And some of them, such as ‘MPAN’, I had to learn to ensure my household electricity supply.

Dear Reader, have you ever heard of an MPAN? Do you have the faintest idea what it is? No, nor did I until about eighteen months ago. I have had to find out as a direct result of the RTS switchoff. The Radio Teleswitch Service (RTS) was a long wave radio signal, which was used to control the times at which household electricity meters switched on certain domestic equipment like storage radiators, to take advantage of off-peak (cheap rate) electricity. It has operated since the 1980s. The signal is being phased out from the end of June 2025 because the equipment is outdated and the parts are no longer available if something wears out.

The discontinuation of the signal means that anybody who uses off-peak electricity for something vital like storage heaters has had to get a smart meter. The smart meter sends a signal to switch on the electricity supply to your storage radiators, hot water heaters etc. Your electricity provider has a number of ‘codes’ which can be applied to your account to set the times of day when the cheap rate is in operation at your home. The meter also transmits readings automatically to your electricity provider which are used to generate your bill. As far as I can understand, it uses cell phone technology in central and southern England, and long-range radio technology in the north including Scotland. It does so via a Data Communications Company server which passes it on to your electricity provider. I have only just found out that when I pay my electricity bill I am not only paying my provider plus SSEN who own the cables and substations, but this communications company which transmits the signal.

It took me months to find all this out, because a year ago the information was not readily available on the internet and nobody, including my (former) provider nor the person I spoke to at the CAB knew enough about it, specifically which signal the smart meters in my area used. I got a variety of confusing answers, unlike today when you can get quite a clear explanation online. In an area with dire mobile phone coverage (improving now since the row over Digital Voice), this question was important. There is also the problem that young people answering telephones may know all about it (or not?), but however willing they may be, they don’t always know how to explain all this clearly over the telephone to novices of any age.

And so to the MPAN.  MPAN is short for “Meter Point Administration Number”, also known as a “supply number” or “S number”. It is a unique 13-digit number which does not change if you change your supplier because it identifies the “electricity supply point” for your home. This number is essential for managing your account. It is NOT the same as the “meter serial number”, a.k.a. Meter ID or MSN, (ten digits), which identifies the physical device doing the metering.

An MPAN can have several meters associated with it, or even no meter at all if the electricity supply is unmetered. Or the opposite. My meter (the physical device) has TWO MPANS, one for the cheap rate electricity that runs my storage radiators, and one for everything else. They each have a separate number and they appear separately on my bill. In fact I usually get two separate bills, because the smart meter isn’t smart enough to send me just one.

It gets worse. One of my two MPANS has two “registers”, one of which does not appear on my bill. Nobody seems to understand why – I have asked. My supplier’s customer service agents have given me several different explanations (don’t get me wrong, they are the best electricity supplier I have had to date). The local charity for helping people with their electricity problems doesn’t understand it. To make matters even more confusing, the register numbers which appear on the meter itself when you are trying to read it are not the same numbers as the MPAN numbers (S-numbers): they are four digit numbers, such “E1-01”. I am currently taking meter readings every day and recording which devices I am using and making huge Excel spread sheets, to try and make some sense of it. After some bad experiences with previous suppliers, I like to check what they say I have consumed against what my meter says. I don’t trust the technology. I have had too many experiences in many areas where technology went wrong.

The ‘Home Display Unit’ is useless because it does not show separate readings for the two different MPANS.

Of course nobody is willing to come out to my home and actually look at the meter themselves. Human technicians cost money, especially on a small island where they have to be shipped in for short periods from the mainland. I have seldom seen anybody as exhausted as the young engineer who installed my smartmeter (working for yet another company); he refused a cup of restorative tea because he had another meter to fit that day and it was going to take him another three hours. He wouldn’t finish until 8pm.

You are often asked to take a photo with your smartphone and email it to them. Fortunately, unlike many people of my age, I do have a smartphone (which really is smart) and I know how to take photos and email them to people. But it still is not so easy. My meter for some reason had to be installed at floor level, and it is difficult for an arthritic old lady to get down on the floor and read it. I have to use a garden kneeler. A friend had hers installed so high up that she needs a ladder to read it. And the display cycles so fast that it is difficult to either take a photo or write the figures down. I did try recording it as a video but my phone refused to transmit it because the file was too large.

Fascinating! But I never needed to know all this until, at the age of 75, I had to have a smart meter. Before, I just had two separate meters.  This is a good illustration of how life is becoming increasingly complicated for older people, unless they have family living nearby. Which more and more of us don’t. Or even then – my nearest (young) relative had never heard of an MPAN. He is living in rented accommodation with no prospect of home ownership. The MPAN is his landlord’s problem.