LONDON, United Kingdom -- Values of UK shopping centers and high street stores could be reduced significantly after property agents were told to reflect the seismic changes sweeping the retail industry, the Sunday Times reported.

The Royal Institution of Chartered Surveyors (RICS) told valuers to be "aware of the potential for significant changes in value" in retail properties, the newspaper reported, without saying where it got the information. RICS also instructed agents to use the widest amount of information to factor in huge changes in shopping patterns, and valuers should take analysis and commentary into account as well as deal prices, the paper said.

Last month's instruction from RICS could lead to bigger asset value declines for retail landlords such as Hammerson Plc, Intu Properties Plc, British Land Co. and Land Securities Group Plc, the Sunday Times said.

UK retailers posted the worst Christmas since 2008 amid the rise of online shopping and increasing concerns about Brexit. More than 20 retail chains instructed accountancy firm Deloitte LLP in the past two months to assess whether they’re able to restructure their debt, the Sunday Times reported last week. Billionaire Philip Green has started a "radical review" of Arcadia and may close scores of shops, according to the Telegraph.

HMV Group Plc has become one of the latest chains to file for insolvency, House of Fraser Ltd. was rescued by Mike Ashley and New Look Retail Group Ltd. recently joined a long list of retailers seeking debt relief. One option for those considering a restructuring is to use company voluntary arrangements, which allow businesses to get more favorable property rental agreements and shut certain stores before their leases expire. Chains such as Marks & Spencer Group Plc are shuttering stores.

Hammerson shares fell 40 percent last year and Intu dropped 55 percent, and Hammerson in April withdrew its offer to buy Intu. The UK is heading for a property crash with average shopping mall values set to drop by 30 percent as yields rise and income falls, Jefferies forecast earlier this month.

By Heather Burke; Editors: Kristine Aquino, Nicholas Larkin and Niveditha Ravi.