Landline/Mobile calls/Broadband - BT Landline and BT Mobile services (including most rental and call prices and the cost of calling or texts to EU countries) will increase on or after 31 March each year from March 2023 by CPI plus 3.9%. This is a 14.4% increase, which is in line with the 10.5% CPI rate of inflation published in January, plus 3.9%