Well, quite:

An NPIA spokesman said: "Because Airwave is a
national system, there’s a need to rationalise the way officers speak
on the radio.

"There’s so much regional diversity
that the use of a common language will increase understanding. This
will be the first time UK police have a nationwide standard phraseology
and procedure." Because airtime on the new system is expensive, brevity
will be encouraged. According to the NPIA, "Regional phrases might take
much longer to say than a clipped national term".

The entire point of a national language (something like the Queen’s English) is that it is understood by everyone. That doesn’t mean that regional accents and variations should not exist, just that they should be used regionally, the national language being used when attempting to communicate nationally.

Now all we need to do is convince the BBC of this.