Information Commissioner Elizabeth Denham has said she was “surprised and disappointed” by the lack of focus on political advertising as an online harm in the Government’s recent proposals to regulate tech companies.

The UK data watchdog boss expressed concerns about an important “gap” in the proposals, following high-profile incidents such as the Cambridge Analytica scandal and suspicious Facebook groups including Mainstream Network, which is accused of spending hundreds of thousands of pounds on the social network to target voters in specific constituencies and promote pro-Brexit messages.

“The white paper is a really important paper and it’s a huge step forward in a route map to identify harms online but I was surprised and disappointed that there wasn’t more focus on what I think is a huge societal harm, which is around electoral interference and the need for more transparency in political advertising,” she told the Sub-Committee on Disinformation.

“It’s surprising to me, and concerning, that the Government hasn’t done a comprehensive examination of political advertising and the oversight that’s needed in this space.

“These are my initial views, but I think it’s a gap that really needs to be addressed by the Government and Parliament.”

The tough new safety laws encompass a number of online harms, ranging from child sexual exploitation, hate crime and terrorism content to cyberbullying, disinformation and advocacy of self-harm.

Labour deputy leader Tom Watson criticised the proposals for not doing enough to tackle so-called “dark digital advertising campaigners”.

Ms Denham, who has been at the helm of the Information Commissioner’s Office (ICO) since July 2016, said the measures were a “good start” but warned that a regulator will need to work with other countries for extraterritorial reach, given that many tech companies are global.

She also stressed the importance of a regulator having “deep and robust information-gathering powers”.

Published jointly by the Department for Digital, Culture, Media and Sport (DCMS) and the Home Office, the white paper proposes strict new rules be introduced that require firms to take responsibility for their users and their safety, as well as the content that appears on their services.

It suggests punishing social media companies with large fines or blocking them from being accessed.

Overseen by an independent regulator, internet companies which break these rules could even see senior management held personally liable for the failings.

A Government spokesman said:  “We are absolutely committed to tackling disinformation and making online political advertising more transparent, which is why we have publicly consulted on making changes to electoral law.

“Our world-leading online harms white paper will help keep UK citizens safe online through a legally-binding duty of care, overseen by an independent regulator.”