Nick Clegg has told the Leveson inquiry that the press "lashed out" at him in panic after he performed well in the televised general election debates.
Following the first debate in April 2010, the first leaders debate ever to be held in the UK, the Liberal Democrats enjoyed a huge surge in support in the opinion polls.
A YouGov poll for The Sun catapulted the party into a remarkable second place on 30%, pushing Labour into third on 28%, with the Conservatives in the lead on 33%.
And with a personal rating of 72%, the Sunday Times observed the Clegg had become "the most popular party leader since Winston Churchill".
However many papers soon turned against the Lib Dem leader, with the Daily Mail running a story headlined: '"Clegg in Nazi slur on Britain".
Speaking at the time Clegg noted: "I must be the only politician in the space of a week to go from Churchill to Nazi."
Clegg told the Leveson inquiry that up until that point his party were the subject of "indifference at best and derision at worst".
He said that many papers operated almost under instructions to "deride or ignore the Lib Dems".
"It must come as a bit of a shock I guess, suddenly to have people you've been ignoring or deriding doing well in a general election campaign," he added.
"The reaction was pretty ferocious ... things were not going according to plan."
Clegg said much of the press viewed his party as "upstarts" who had intruded on the two party fight between the Conservatives and Labour.
He said the papers had a "panic" and started to "lash out a bit" at him.
"I didn't find it surprising," he said. "That's the nature of the alignment between particular parties and particular papers."
"If suddenly the yellow team comes in you want to get them off the field of play."