Alexander Baron and his associate Mark Taha, have between them issued defamation writs against 22 different defendants, including Gerry Gable, the magazine's editor and publisher. Anyone claiming libel can sue not only the author, editor and publisher, but also bookshops and libraries.
Bookshops object that it is all but impossible to vet material and that the law is particularly unfair when, as small concerns, they cannot afford to defend libel actions even when a defence might be open to them.
Mr Baron has so far collected damages and costs from approaching a dozen different defendants.
In one of the cases, the Centreprise Trust in Hackney, north London, felt compelled to settle even though it said it had not stocked the relevant issue of Searchlight.
Housmans, the north London pacifist bookshop, and Bookmarks, official bookseller to the Trades Union Congress, are among the other defendants who have paid to settle claims in two writs from Mr Baron.
Mr Baron then celebrated one of the payouts by proclaiming in a pamphlet, Poison on the Rates, in a strenuous critique of Centreprise: "It was financed by a donation from Housmans Bookshop Limited . . . I owe all these people a debt of thanks."
Housmans has since suspended sales of Searchlight.
Mr Baron, an assiduous publisher of right-wing literature, interrupted a Commons Home Affairs Select Committee hearing evidence on organised racism to serve a writ on Mr Gable.
Another writ, from Mr Taha, who carries out research for Mr Baron's south London publishing organisation, names six defendants - the two bookshops, distributors and printers, and Mr Gable.
Mr Gable, an anti-racist activist for more than 30 years, is refusing to settle either action.
The shops could try to plead the defence of "innocent dissemination" in response to the writ from Mr Taha, but say that the cost of a court defence is beyond their resources.
Jeremy Corbyn, Labour MP for Islington North, has put down an amendment for Monday night's remaining stages of the Defamation Bill urging that in cases involving "second-tier" defendants, plaintiffs should have to show that the innocent dissemination defence is unlikely to succeed before being allowed to press on with their case.
Bookmarks and Housmans - which appears to be particular target because it stocks gay material - claim they have been singled out for their political agenda.
A libel fund appeal has attracted support from Bruce Kent, the writers Iain Banks and Harold Pinter, the film-maker Ken Loach, the TUC General Secretary John Monks, and MPs.
Mr Baron is not a man to be easily put off. He had to give an undertaking relating to his behaviour after an incident at the offices of Bindmans, Mr Gable's then solicitors, last year.
When Housmans complained about the reference to a "donation" in the Centreprise pamphlet, he replied: "I will be passing on copies of your letter to various publications, including far right publications, so that a wider public can see and appreciate the sort of slime you are . . . Now go away and don't bother me again you obnoxious little shit."
When approached by the Independent, Mr Baron said: "I am not commenting until the cases are over."