The 27-year-old moves to the Potters after four years with the Royals where he was a mainstay of the squad that claimed promotion to the Premier League although his appearances in their two-year stay in the top flight were restricted by injury.

The deal will initially cost the newly-promoted club £2million potentially rising to £2.25million.

Stoke chief executive Tony Scholes told the club's official website: "We are delighted to make Ibrahima the club's latest signing.

"He is a quality addition to the squad and comes with plenty of Premier League experience having played in the top flight with Reading."

Sonko made 122 league starts for the Royals following his transfer from Brentford and quickly established himself at the heart of their central defence.

He has captained Senegal Under-23s but is still eligible to play for France - where he lived from the age of six months - because his only appearance for the Senegal senior side came in an unofficial friendly.

Reading director of football Nick Hammond told the club's official website: "Ibrahima Sonko has been a terrific performer in the club's recent development.

"But centre-half is a particularly strong position for us in terms of both quality and quantity, especially with the continuing emergence of Alex Pearce, who adds to the experience offered by Ivar Ingimarsson, Michael Duberry and Andre Bikey.

"Bearing that in mind, we felt the timing is right for this deal and it is probably a good time for Ibrahima to seek a fresh challenge."