It is the system that dates back to Alexander Bell's original creation more than 140 years ago.

But the traditional copper-wire telephone network is to be phased out of Parliament entirely within the next eight months, because the replacements for aging parts are no longer manufactured.

Instead, MPs and peers will use the Skype internet telephony service - albeit with a option of connecting to the system with handsets designed like traditional telephones.

Parliamentary authorities made the decision to switch to a "voice over internet protocol (VOIP)" system - the like of which BT is gradually rolling out across the country - after being told by officials that the Palace of Westminster's copper wire network was "at the end of its supported life".