The Conservatives are "annoyed" former party treasurer and general election pollster Lord Ashcroft shares the results of his revealing surveys with all parties.
In March, the former Tory peer resigned from the House of Lords to focus on his Lord Ashcroft Polls service, which predicts how decisive marginal seats could vote on 7 May.
Results from the surveys have become compulsive reading by parties and commentators alike, who view them as a snapshot of how the election could unfold.
But, according to a Financial Times report, the Conservatives would rather the 69-year-old provided results exclusively for the Tories.
"He is giving away polling that only we can afford to do to our competitors," a senior Tory Cabinet minister told the paper. "It kills our competitive advantage. For a Tory peer to do that, well, it's annoying but he's done it now."
The report also claimed Ashcroft was motivated to published the polls by spite towards Tory election strategist Lynton Crosby.
The Australian was hired by Conservative HQ for 2005's unsuccessful election campaign and was handed the job of masterminding the 2015 race after successfully plotting Boris Johnson's ascent to mayor of London.