LONDON, United Kingdom — Five UK agencies that represent models got taken to the dog house by a UK regulator that said they colluded on the prices charged to fashion retailers.

FM Models, Models 1, Premier, Storm, Viva, and their trade group, the Association of Model Agents, were fined a total of £1.5 million ($1.8 million) by the UK Competition and Markets Authority Friday. The companies fixed prices from at least April 2013 until March 2015, the regulator said.

"In this case the agencies and the AMA colluded with each other over their approach to pricing and, in some instances, the agencies agreed to fix minimum prices," John Wotton, chair of the case decision group at the CMA, said in a statement. "This type of behaviour harms the economy and deprives businesses and consumers of the benefits of competition."

The CMA’s investigation related to fashion magazine shoots offering model fees of a few hundred pounds to advertising campaigns offering over £10,000. The agencies agreed to fix minimum prices or agreed a common approach to pricing for customers including "well-known high-street chains, online fashion retailers and consumer goods brands."

Andy Mills, a spokesman for Models 1, Premier and Storm, said the CMA’s findings were "wholly mistaken" and the companies will appeal.

"The CMA’s statement does not reflect a thorough understanding of the market for modelling agencies in the UK, notably the role which agencies play in protecting the interests of models," said Mills. "The CMA has not stated evidence of any discernible effect on competition in the UK."

Viva also denied that it was part of any plot to fix prices.

By Patrick Gower, with assistance from Paul Jarvis; editor: Anthony Aarons.