According to Twitter, the First View service gave Labour “exclusive ownership of Twitter’s most valuable advertising real estate for a 24-hour period”.
Twitter has denied claims of political partisanship by saying that its service was a commercial product available to all political parties.
A Twitter spokesman said: “First View is a paid-for advertising product that means when users first visit the Twitter app or log in to twitter.com, the top advertising slot in their timeline will be from that advertiser’s brand.
Tom Lavelle, Head of Digital Campaigns at the Labour party, said on Twitter’s website: “Twitter First View allowed us to reach everyone in the UK.
“We were also able to ensure our message was the first thing people saw when going onto Twitter.
The news has come after the Conservatives were criticised for running a far less effective social media campaign than Labour in the lead up to June’s general election.
Data from We Are Social, an agency, revealed that the Labour Party increased its following by 61 per cent across Facebook, Twitter and Instagram in the six weeks after the election was called. The Conservatives’ following rose by just six per cent in the same period.
The Labour Party used Twitter’s First View service