Google's DoubleClick ad technology, Yahoo and AOL have all been awarded seals confirming they meet industry-agreed standards to protect brands' safety online.

The companies join Microsoft, Quantcast, Ignition One and 17 other firms who have received the certification in the UK, awarded by the UK's Joint Industry Committee for Web Standards (JICWEBS), an independent body that defines best practice and standards for online ad trading.

The certification proves that companies have had their advertising misplacement policies and processes verified by JICWEBS, and confirmed to reduce the risk of online ads being served next to inappropriate or illegal content.

19 other companies have committed to undergo verification in the next six months, as advertisers and agencies place more focus on maintaining their brands' reputation.

"Brand safety has never been more important to marketers, especially given the rapid rise of programmatic display," said Guy Phillipson, CEO of the IAB UK. "The impressive number of companies committed to this initiative is testament to the industry's willingness to respond with audited best practice."

"The number of companies who've achieved a seal or committed to independent verification has more than doubled in four months," said Richard Foan, facilitator for JICWEBS. "Effective oversight by JICWEBS has delivered true cross-industry standards which deliver transparency and increase trust."