"She's a liar, liar. You can't trust her, no, no, no no," goes the song by seven-piece band Captain Ska, interspersed with audio clips from May as well as references to school, health service and police cuts.
"Liar, Liar GE2017" was released last Friday with the support of the People's Assembly Against Austerity, a left- wing group that has mounted large protests against the Conservative government's budget cuts.
The band played the song at a small but rowdy protest near the BBC in London on Friday, shouting over the sounds of BBC radio playing the top songs in the charts.
"Our message is that people do have the power to change society if we act together," they said.
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The track was the highest new entry on the official singles chart.
It was originally released in 2010 in response to the creation of the previous Conservative-led coalition government under prime minister David Cameron.
BBC Radio 1 said the song would not be played as part of the official chart countdown on Friday due to rules governing the campaign ahead of the June 8 vote.
All proceeds of the song -- a remix of a 2010 tune --- sold before election day will be donated to food banks and to The People's Assembly.
Meanwhile The Beatles' landmark album "Sgt. Pepper's Lonely Hearts Club Band" has returned to number one with a remastered version to celebrate 50 years since it was first released in 1967.
The record is the best-selling studio album ever in Britain and the third biggest-selling album of all time in the country, behind Queen's "Greatest Hits" and ABBA's "Gold" compilations, having shifted 5.2 million copies.