The Competition and Markets Authority (CMA) has appointed a four-strong panel to conduct the inquiry into Bristol Water’s appeal following its decision to reject Ofwat’s final determination for the upcoming AMP6 investment period.

Ofwat referred the appeal to the CMA following the water company’s decision to reject the regulator’s final determination on water price limits for the period 2015 to 2020, broadly on the grounds that they were too low.

Robin Aaronson, an economist specialising in competition policy, is the only member who belongs to the CMA's specialist utility panel. Other members of the inquiry group are:

• Anne Lambert CMG - currently a member of the Performance Review Body which advises the European Commission on regulation of air traffic management.
• Katherine Holmes – previously a competition lawyer for a number of organisations and a former Chairman of the Joint Working Party of the Bars and Law Societies of the UK on Competition Law.
• Stephen Oram – previously Director of the Newspaper Publishers Association. Current roles include Director of the London Press Club and non-executive Chairman of a national newspaper advertising consumer protection scheme. He is also a member of the specialist communications panel and the newspaper panel.

The CMA, the UK’s primary competition and consumer authority, will now determine the appeal and, if necessary, set new price limits. All the CMA’s functions in price determination appeals are performed by inquiry groups chosen from the CMA’s panel members which act as the decision-makers. Deadline for a decision on the appeal is 3 September 2015.

In April 2014 it took over the functions of the Competition Commission which undertook a similar exercise in 2010. Ofwat referred an appeal from Bristol Water in February 2010, following its rejection of the regulator's final determination on price limits for the period 2010–15. Again, Bristol Water's appeal was broadly on the grounds that they were too low.

At the time the Competition Commission decided that Bristol Water could make a small increase in the prices it charges its customers above the five-year price limits previously set by Ofwat.