The News Media Association has called for reform to competition regulation in order to address concerns over Google and Facebook’s ad market dominance.

The group, which represents national, regional and local news publishers in the UK, warned the web giants, known collectively as the Duopoly, are “jeopardising the sustainability of quality journalism”.

Total advertising spend in the UK grew by 4.6 per cent to a record £22.2bn in 2017, but Google and Facebook took the lion’s share as news publishers got a diminishing slice of the pie.