If the noise seems to be a short recurring beep, make sure it's not a smoke alarm or carbon monoxide detector nearby that's running low on battery.
If the meter appears to be humming, check if there's anything leaning on the meter or nearby surfaces which might be causing a vibrating noise.
If none of the above seems to be the case, please do the following:
If it's your gas meter, call the National Grid Gas Emergency Line on 0800 111 999. If they advise you to get in touch with us, please visit our emergency page here for more info: https://octopus.energy/emergency/
If it's your electricity meter, please visit our emergency page here for more info: https://octopus.energy/emergency/