Casting doubt on the Sun's claim that "It's the Sun wot won it" at the last election, research suggests that the calls last year by normally Conservative papers for John Major to go, and the move by the Sun to a less hostile posture towards Labour have had no impact on readers' political views.
John Curtice, of the University of Strathclyde, looked at the newspaper- reading habits and political views of 1,317 voters, interviewed every year between 1992 and 1995 for the British Election Panel Survey.
Readers of the Sun certainly noticed that their paper had changed its allegiance, with a drop from 83 to 51 per cent in the proportion who believed it backed the Tories.
Other pro-Tory papers show smaller falls, with only readers of the Daily Telegraph believing it has remained loyal to the Tories. In 1992, 82 per cent ofDaily Telegraph readers thought it backed the Tories, compared to 80 per cent in 1995.
Daily Mirror and Guardian readers, by contrast, showed no change in their conviction that their papers supported Labour.
But the study found that Labour picked up more new supporters from readers of the Daily Mirror than of the Sun.
One of the reasons was that Daily Mirror readers were more likely to take a pessimistic view of the state of the economy.
But generally newspapers seem to have no discernible impact on readers' images of the parties or their leaders.
The study found no difference in how the Prime Minister was rated by readers of the "rebel Tory press" (the Sun, Daily Mail, The Times, and Star) and the "loyal press" (the Daily Telegraph and the Daily Express), despite the rebels' call for Mr Major to be ousted in last year's Tory leadership battle.
Similarly, there was no evidence of any link between newspaper readership and opinions about the Labour leader, "despite the relatively favourable coverage which Tony Blair has received in the traditionally Tory press", Dr Curtice writes.
The findings do not necessarily confound the strategy of Alastair Campbell, the Labour leader's press secretary, of wooing the Tory press.
"It may have stopped the Tory press playing its usual role of acting as a source of reinforcement for the Conservatives," comments Dr Curtice. Last year Mr Blair travelled to Australia as the guest of Rupert Murdoch to speak to executives of his NewsCorp global media empire.
But Dr Curtice writes: "There is little evidence to suggest that either politicians or journalists should be as preoccupied with the partisan tone of the press as they often appear to be. The changed tone of the Tory press since 1992 may have been entertaining for journalists to read and a source of some self-satisfaction for Labour's spin doctors. But ... Mr Blair's best friend continues to be the Daily Mirror, not the Sun. Labour has been most likely to make converts among those who read the Daily Mirror and to lose friends among those who stop reading that paper."
He concludes that, overall, "the influence of the press is at most only a marginal one".
The effects that there are seem small, and the net effect of the partisan press appeared to be zero.
There was no difference between the swing to Labour since 1992 among readers of partisan papers, Labour and Tory, taken as a whole, and the swing among non-readers and readers of the "non-partisan press", including the The Independent. Which suggests that, taken together, the partisan papers have no impact on their readers, either in a pro-Tory or a pro- Labour direction.