Brentford have signed defender Jake Bidwell from Everton for an undisclosed fee.
Bidwell, 20, completed two separate loan periods in the previous two seasons at the League One club, making 75 appearances in total for Uwe Rosler's side.
The left-sided player, who has represented England at underage levels up to Under-19, has agreed a contract that will keep him at Griffin Park until the summer of 2016.
Bidwell came through the Everton academy and made his first team debut for in a Europa League tie against BATE Borisov in December 2009.
Brentford's sporting director, Mark Warburton, said: "We are absolutely delighted to see a young player of Jake's talent and ability commit his long term future to the club.
"Over the last two seasons, Jake has delivered a consistently high level of performance and his desire and determination to give everything to the cause has been clear for all to see.
"He has displayed a maturity beyond his years and his all-round professionalism both on and off the pitch is an outstanding example for all other young players.
"For Brentford Football Club it is vital that we secure the quality of player that will give us very real opportunity to achieve our long term goals.
"With Jake committing in this way, it is another very positive step forwards and we look forward to watching his continued progress in the seasons ahead."