I've heard about this one via my father who you spoke to in Inverness, if your the same bloke.

Anyways, as a mech eng who works with big machines - 115db is very loud, however harm and discomfort levels to humans are also dependent upon not just the db level, but also the vibrational frequency of the sound. Of course you wouldnt expect our elite police force in this country to know about that...

I'd want to see firstly, proof the test was carried out correctly- as has been said it sounds lke it should not have been placed directly inside the exhaust- Doing that will directly restrict the noise reducing properties of it which I cant believe is correct procedure- which more than likely explains the reading.

Secondly I would want to see calibration certification for the decibel meter, along with confirmation that the procedure underaken to do so is correct and the meter itself is of sufficent accuarcy for prosecutional purposes.

Thirdly I would want to see proof that the officers themselves are correctly trained for the adminstration of the test correctly, which ties back into point one.

At the end of the day it's a minor thirty pound fine for a minor offence, create enough fuss and I suspect nothing will come of it.