The Liberal Democrats are preparing for the "very considerable chance" there will be a snap election next year.
The memo was written by campaigns chairman Mr Davey
They are holding a two-day meeting to focus on their election strategy should Gordon Brown take over from Tony Blair.
In a leaked memo Lib Dem campaigns chairman Ed Davey says that if Mr Brown takes over in May or June, there is a good chance of an October election.
He adds that senior Lib Dems should "turn their fire" on Mr Brown's legacy as chancellor.
Mr Davey also said the challenge in the run-up to the Scottish, Welsh and local elections was to "project... a strong sense of who we are and our fundamental beliefs".
Speaking to the BBC later, Lib Dem leader Sir Menzies Campbell confirmed that preparations had begun for the next election.
"I think everyone now accepts that Gordon Brown is likely to be the next leader of the Labour Party and as a result, to be prime minister.
"And it's not impossible that he might think that perhaps he ought to have a snap general election, perhaps as soon as this time next year.
"We have already started the preparation of our manifesto, if that is the time when the election takes place, I have appointed Chris Rennard who's chief executive of our party, to be the chairman of the General Election campaign committee."