Chris Marinello, a former specialist at ALR who launched the Art Recovery Group in 2013, has accused his former employees of trying to push him out of the market.
The two competing firms have been in dispute since Marinello launched a database of stolen, looted or missing works of art in January 2015. At the time, ATG described the new service as "a clear challenge to the pre-eminence of the Art Loss Register database, which has dominated the due diligence and recovery sector for the past 25 years".
Marinello promised an alternative service saying: "The art market would not be well served with only one auction house or just one art gallery, so why shouldn't consumers be offered a choice in due diligence providers?"
However, by July, ALR had filed a High Court civil claim accusing their former employee and others of "the unlawful establishment and operation" of ARG, citing breach of contract, breach of confidence and "infringement of database rights".
A counterclaim filed by Marinello in November stated "each and every allegation contained in the particulars of the claim is denied".
In the latest salvo, ARG has sent a letter to the competition authorities accusing the ALR of "implementing a persistent, pervasive and systematic plan to eliminate ARG from the market". The Competition and Markets Authority has not said if it will investigate ARG's complaint.
Launched in 1991, the ALR's database has provided a due diligence service to dealers, auctioneers, insurers and private individuals. The firm is run by Julian Radcliffe, with Sotheby's, Christie's and the BADA among the minority shareholders. More than 90 auction houses subscribe to the service.