Vodafone and Three UK have pledged to cap their lowest-cost mobile plans at £10 for two years, as the companies hope to convince the UK’s competition watchdog to approve their £15 billion merger. The Competition and Markets Authority (CMA) has been investigating the mega-deal since it was announced last summer,

After BT warned that a £15 billion merger between Vodafone and Three UK would cause prices to skyrocket, the two companies have come out swinging — pledging to cap their lowest-cost mobile plans at £10 for two years.

Vodafone and Three UK have pledged to cap their lowest-cost mobile plans at £10 for two years, as they hope to convince watchdogs to approve their £15bn merger.

Vodafone Group Plc and CK Hutchison Holdings Ltd.’s Three told antitrust regulators they’ll keep a £10-per-month plan available for two years if the companies are allowed to merge in the UK.