How a UK callsign is built
A UK amateur callsign has a prefix of G, M or 2, an optional regional letter, a digit, and a suffix of two or three letters. The prefix and digit together show the licence level and roughly when the call was issued. M7ABC is a Foundation licence, 2E0ABC and M8ABC are Intermediate, and G4ABC and M0ABC are Full. Calls are issued in sequence, so a G3 call is older than a G4, and two-letter suffixes such as G3AB come from the earliest series.
Regional secondary locators
The optional second letter is the regional secondary locator (RSL). It shows which part of the UK, the Isle of Man or the Channel Islands the station is in: GM for Scotland, GW for Wales, GI for Northern Ireland and so on. Club stations use a different letter, so GS is a Scottish club and GX an English one. Since the new licence in February 2024, using an RSL is optional for G and M calls. It's still compulsory for 2-series calls, where it's part of the call itself.
The 2024 and 2025 changes
Ofcom brought in a new amateur licence in February 2024. It raised the power limits to 25 W for Foundation, 100 W for Intermediate and 1 kW for Full licences, made RSLs optional, and allowed any suffix as long as the station stays identifiable. In October 2025 the remaining changes went live in Ofcom's licensing portal. New Intermediate licensees now get M8 or M9 calls instead of 2E0 or 2E1, and existing holders can swap: 2E0ABC becomes M8ABC and 2E1ABC becomes M9ABC. Ofcom is moving towards one personal call per person, and lower-level calls are now revoked when you upgrade.
Suffixes after the call
/P means portable, operating away from the main station address, and /M means mobile in a vehicle. /MM is maritime mobile, on a boat at sea, and /A means an alternative address. Under the 2024 licence these suffixes are no longer compulsory, but many operators still use them, especially in contests and awards that count portable activations.
Visiting the UK
Amateurs from other countries that apply CEPT Recommendation T/R 61-01 can operate in the UK for up to three months without a UK licence. They put M/ in front of their own callsign, or the regional form such as MM/ in Scotland or MW/ in Wales. For example, a German amateur in Scotland might sign MM/DL1ABC.
Questions
What licence does an M7 callsign mean?
M7 is a Foundation licence, the entry level, with a 25 W power limit. M3 and M6 calls are also Foundation.
What is an M8 or M9 callsign?
An Intermediate licence. Since October 2025 Ofcom has issued M8 and M9 calls to new Intermediate licensees instead of 2E0 and 2E1, and existing 2-series holders can switch to the matching M8 or M9 call.
What does GM or GW mean?
The second letter is the regional secondary locator. GM is Scotland, GW Wales, GI Northern Ireland, GD the Isle of Man, GJ Jersey and GU Guernsey. Plain G, or GE, is England.
Can I check if a callsign is available?
Not from here. When you apply for a licence, Ofcom's online licensing portal shows the calls available to you.
What is a GB callsign?
GB calls are for special event stations, such as anniversaries, shows and activity days. GB3 and GB7 calls are used by repeaters and beacons.