Consumer champion Martin Lewis has won a High Court battle to protect his own "Money Saving Expert" trademark from "exploitation".
The founder of the Moneysavingexpert.com website accused Client Connection Limited (CCL), which operates a claims management business involving cold-calling, of infringing his mark.
Among other things, CCL deals with claims arising out of mis-sold payment protection insurance.
Mr Lewis scored a legal victory at London's High Court on Wednesday when a judge ruled the mark was "distinctive to the claimant".
The judge said the evidence showed that CCL "was riding on the coat tails of the claimant's registered mark and benefiting from its power of attraction, its reputation and its prestige".
Mr Lewis recently topped The Grocer magazine's annual Power 100 list and the title of "most powerful person on the high street". His website has five million followers and he was praised for offering advice, helping shoppers avoid rip-offs and getting the best deals.
Grocer editor Adam Leyland said: "With his free weekly emails and appearances on ITV's Daybreak, we believe he tops Tesco in terms of power." There was evidence that some 11.3 million people visited his website between December 2010 and March 2011.
Until last September, CCL operated under the name "Money Claiming Experts". Mr Lewis complained that during calls it held itself out as "Money Saving Expert", or was heard by witnesses describing itself as such.
On Wednesday, Mr Justice Norris, sitting in the Chancery Division of the High Court, ruled Mr Lewis was entitled to a summary judgment against CCL.
The judge said the evidence demonstrated "conclusively" that witnesses identified Mr Lewis - and no-one else - with the name "money saving expert".