Cleckheaton folk will have to use their area code even when dialling local numbers from next year.
Currently phone users only have to insert the 01274 code if they are dialling a number outside the Bradford area.
But increasing demand for new numbers means supplies are running low, according to Ofcom.
So as of October 1 people will have to include it when making all calls from their landlines – as they currently do when calling from mobile phones – in order to free up new numbers.
The number of communications providers offering services in the Bradford area – including Cleckheaton, Gomersal, Birkenshaw and parts of Hightown – has increased over the last 10 years, leading to more competition and cheaper landline bills. But it has also led to increased pressure on the supply of new phone numbers.
Ofcom’s Chia Seiler said: “Asking callers to use the 01274 code locally is designed to safeguard the future supply of new landline numbers, and avoid the need for measures such as changing existing phone numbers.
“The cost of calls won’t be affected, and those who dial without the area code after the change will hear a recorded message asking them to include it.”
Ofcom will work with telephone companies to ensure callers are informed of the change in good time, and the local community is prepared.
Callers with a Wakefield code, 01924, will not be affected.