Equifax claims that despite new regulations, which came into effect for this autumn's canvas, Haringey, Epsom & Ewell and East Hampshire District are all issuing pre-ticked forms to those who opted out in the previous year.
The new regulations were passed by the House of Commons in July as a result of lobbying by Equifax, the DMA and other industry players, who believe the practice was infringing consumer choice.
Pre-ticking also hits businesses that rely on direct marketing as a communications channel by reducing the number people they could mail to.
John Gray, operations director of Equifax, said: "We believe that the increased number of opt-outs by electors actually resulted in a more responsive list that marketers could utilise with complementary information sources. However, by pre-ticking the opt-out option on the electoral roll forms, local authorities will restrict consumer choice and business opportunities alike."
The number of electors opting out of their data being used for commercial purposes rose by 2.4m from 20% in 2002 to 26% in 2003.
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