12.2 per cent of UK display ad impressions in Q2 2015 were fraudulent, according to an Integral Ad Science report – equivalent to £277m of the total UK online ad budget.

“Fraud is at the forefront of the media quality debate, and when we see figures in the order of nearly £300m being siphoned off from ad budgets, we understand why advertisers like Unilever and Nestlé are voicing concerns,” said Integral UK managing director Niall Hogan. “It is essential that we come together as an industry, through initiatives like the JICWEBS anti-fraud group, to educate and build advertiser confidence in the ways that we can address potential media quality issues.”

Looking at impressions served through ad exchanges and networks account, the proportion of fraudulent impressions rises to 13.6 per cent, compared to 6.6 per cent for those bought direct from publishers.

The report, which is based on hundreds of billions of impressions between April and June, notes a similar correlation when it comes to brand safety and viewability.

13.6 per cent of network and exchange impressions were considered to have a moderate to very high risk of inappropriate placement, compared to 6.3 per cent for direct publisher buying. The biggest category of inappropriate content was adult (37.8 per cent), followed by violence (29.6 per cent) and illegal drugs (13.6 per cent).

Overall, 55.4 per cent of impressions during the quarter were viewable, as per the MRC standard. For networks and exchanges, that figure drops slightly, to 52.1 per cent – but publisher-bought impressions saw a significantly higher 63.4 per cent.

If you want to learn more about fraud, viewability or brand safety, read our Big Issues series, which covers all three topics.