The European Commission has published guidance to help the EU’s telecoms regulators (Ofcom in the UK) calculate the wholesale termination rates charged when mobile and fixed-line operators connect calls from another network. Although the guidelines aren’t mandatory, regulators are obliged to take the "utmost account" of them. The EC says national termination rates should only be based on the actual costs, calculating that the removal of artificial price differences could save customers at least €2 billion in the next three years.