By default the English language voice prompts that Asterisk comes with have an American accent. There are some free UK voice prompts available and below are instructions for downloading and installing those. The instructions below will replace the existing US prompts with the UK ones.
The prompts can be found here – http://www.enicomms.com/cutglassivr/
More details about different language voice prompts can be found here – http://www.voip-info.org/wiki/view/Asterisk+sound+files+international
The commands below download the wav, ulaw, alaw, g729 and g723 codec versions.
First create a folder to download the files to –