Political parties are set to be forced to include "digital imprints" on all of their online campaign materials as part of a Cabinet Office plan to tackle misinformation.
Under plans unveiled by the Cabinet Office, online adverts will have to be labelled to show who has produced and paid for them.
It comes after years of pressure from transparency groups and regulatory bodies, who had warned of the dangers of misinformation being spread through unregulated online campaigning.
In 2018, the Electoral Commission, the UK's election watchdog, warned the lack of oversight on digital campaigning had left "democracy under threat".
The new proposals would bring online campaigning in line with regular printed political leaflets which are legally obligated to include details about which organisation or campaign group had produced and paid for them.
Unveiling the plans, constitution and devolution minister Chloe Smith, said: "People want to engage with politics online. That's where campaigners connect with voters and is why ahead of elections, almost half of political advertising budgets are now spent on digital content and activity."
She added: "But people want to know who is talking. Voters value transparency, so we must ensure that there are clear rules to help them see who is behind campaign content online.
"The measures we have outlined today are a big step forward towards making UK politics even more transparent and would lead to one of the most comprehensive set of regulations operating in the world today."
The proposals would see all registered political parties and campaigners forced to include the imprint on all paid and organic digital content, with other campaigners only expected to include the information on campaign material they had paid to promote.
Earlier this year, the Lords Democracy and Digital Technologies Committee had urged ministers to introduce imprints as part of a wider package of measures to tackle a "pandemic of misinformation".
And the cross-party group of peers said the government should go further by handing new powers to the Electoral Commission to impose fines of up to £500,000 on those who continued to spread "fundamentally inaccurate" messaging during elections.
Responding to the Cabinet Office plans, a spokesperson for the Electoral Commission said: “This is a welcome opportunity to deliver real change for voters and provide them with a better understanding of who is trying to reach them online."
And they added: “The use of digital tools for election and referendum campaigning is extensive, and we know that many voters are increasingly concerned about truth, transparency and the targeting of political advertisements.
“We have recommended extending imprint requirements to digital election and referendum material so we look forward to considering the government’s proposals and the opportunity to deliver real benefits for voters, parties and campaigners.”
John Johnston is a reporter for PoliticsHome, where a version of this story first appeared.