The ISBA Programmatic Supply Chain Transparency Study, which was carried out by PwC in association with the Association of Publishers, also found that on average only 51% of advertising spend made its way to online publishers.

The study is based on data collected from 15 advertisers, eight agencies, five demand side platforms (DSPs), six supply side platforms (SSPs) and 12 publishers, which together account for £100m UK programmatic media spend.

The study used real market data to look at each part of the supply chain, the services delivered and the costs at each stage.

The ISBA said the intention was to provide a more transparent view of the UK programmatic supply chain, for the benefit of all participants and the industry as a whole.

The study marked the first time that programmatic advertising supply chains – the way in which advertisers and publishers are served by the programmatic advertisement delivery system – have been mapped from end to end.

Researchers found problems in how ad tech suppliers shared data, an inconsistency in data storage and formatting, and that data captured by a DSP for an impression was not equally captured by SSPs, hindering impression matching.

The ISBA recommended standardisation across a number of areas to help improve data-sharing and transparency, and to work together to further investigate spending that was unaccounted for. A cross-industry taskforce has been set up to work on these two issues.

Phil Smith, director general of the ISBA, said: “This process has been led by our members, advertisers who proactively sought to understand a problem and find a way forward.

“The challenge now is for industry to come together, as they will in the new taskforce, to drive industry standards and create transparent supply chains, to allow companies and consumers to benefit properly from online advertising.”