Lib Dem conference: Tax rise mooted in email error
Lib Dems would raise taxes on higher earners, according to a private memo inadvertently sent to journalists.
The email was apparently intended for party spokespeople.
As well as spelling out what interviewees should say to the media, it said the party was looking at how people earning more than £50,000 could make a further tax contribution.
Senior Lib Dem Vince Cable said the proposal was not government policy and he did not know where it had come from.
Party officials said it had been mistakenly included from an out-of-date briefing.
Under the heading "fairer taxes", the memo said: "It is unrealistic to cut more money from welfare spending without increasing taxes on Britain's richest."
Earlier, party leader Nick Clegg told delegates he was opposed to the idea that the deficit should be reduced by spending cuts alone, without higher taxes playing a part.
"We will go into the next election in favour of more fair taxes and not follow George Osborne's plan to make further savings out of spending cuts."
Although the Lib Dem leader has hinted at raising taxes on those earning over £50,000 before, he has not raised it recently, instead tending to emphasise plans to levy a 1% "mansion tax" on properties over £2m, said BBC deputy political editor James Landale.
Officials said the internal party memo was simply repeating what Mr Clegg had said in interviews a year ago.
As well as policy proposals, the document also advised party spokespeople on how to deal with questions on a range of topics - from housing benefit changes to the party's handling of sexual harassment allegations.
It listed what officials call the Lib Dems' "key achievements in government".
And it set out lines of attack against the party's election rivals and potential future coalition partners.
In one passage, the briefing document says Ed Miliband is a "weak leader of a divided party".
Labour "crashed the economy", the document goes on, and "cannot be trusted".
The section attacking the Tories reminded conference delegates the party had blocked a number of proposals put forward by the other half of the coalition - on inheritance tax, allowing schools to be "run for profit" and letting companies "fire staff at will".
"The Conservatives on their own cannot build a fairer society," it added.
But Treasury Chief Secretary Danny Alexander said: "I haven't seen this memo. I don't know what it is."