Google has made its voice calling service for Gmail available to users in the UK.

The Gmail voice calling service, which was first made available in the US last year, differs from Google's three-year old Gmail voice and video chat that gives users an audio and visual experience online, by allowing users to dial phone numbers.

The search engine has now rolled out the service, which is fairly easy to use and just requires callers to press Call phone at the top of the chat list and enter a number or a contact name, to 150 countries including the UK.

Gmail calls in the US and Canada are free of charge. However, users in other countries will have to pay for their calls, with prices in the UK starting from 2p per minute for calls to landlines and 11p per minute for calls to mobiles. For a full list of calling costs visit Google's dedicated web page.

Users can choose between paying for calls in Sterling, as well as Euros, Canadian dollars or US dollars and Google revealed there are no connection charges.

"We're rolling out this feature over the next few days, so if it's available in your country you'll see a little green phone icon show up at the top of your chat list and you'll be ready to make calls (you'll need to install the voice and video plug-in if you haven't already)," said product manager for the Gmail team, Pierre Lebeau, in a blog.

Google App users can also access the service but the Google Voice and Google Checkout must first be enabled in the administrator control panel.