Conversation so far:
What did he try?
In his last general election as leader, in May 2005.
What was his strategy?
election targeting the seats held by the most senior and/or highly regarded Conservative MPs, dubbed a "decapitation" strategy.
Waht did this do?
the Conservatives would be discredited as the official opposition allowing Kennedy and the Liberal Democrats to claim that they were the "effective opposition.
Did this work out the way he wanted?
At the same time they also hoped to capture marginal Labour seats attracting (particularly Muslim) Labour voters who were dissatisfied because of the invasion of Iraq.
Waht did this do?
They had succeeded with this tactic in by-elections, taking Brent East and Leicester South from Labour.

Question: What did the election review?
Self-contained rewrite: What did the by-elections accomplish?