Strong revenue growth and expanded margins, particularly in its mobile phone network operations, helped AT&T, the largest US telecommunications group, report a 21.5 per cent increase in first quarter net earnings and its 12th consecutive quarter of double-digit growth in adjusted earnings per share.

”We delivered an excellent first quarter and a solid start to the year,” said Randall Stephenson, AT&T chairman and chief executive officer. ”Revenue growth continues to ramp, we have good momentum across key growth areas, major cost initiatives are on track, and our operational results reinforce the confidence we have in our outlook.