Bees secure promotion and League Two title
Brentford's 3-1 win over Darlington means they will start next season in League One as League Two champions.
Darlington were reduced to ten men in the second minute when Alan Whitewas sent off for a reckless elbow.
Skipper Alan Bennett then gave the Bees a 35th minute lead with a low shot.
Clarke, a former Darlington loanee, increased the Brentford lead with a close-range header from a David Hunt free kick.
Clarke then secured the win for Brentford when he fired in his second goal of the game and 18th of the season in the 53rd minute with low left-foot drive.
Pawel Abbott gave Darlo a 59th minute glimmer of hope but it turned out to be mere consolation.