It was reported this week that Camden had rejected a road closure request by campaign group Republic for the event, saying 'many local businesses' were opposed.
However, Republic's executive officer Graham Smith claimed that the local businesses he spoke to were in favour of, or ambivalent about, the proposed street party in Covent Garden on 29 April.
The Metropolitan Police had also accepted Republic's management plan for the event, in Earlham Street in the Seven Dials area.
PRWeek understands that significant opposition to the plan came from Shaftesbury Plc, which owns a number of properties in Covent Garden that house shops and restaurants.
Smith insisted that Shaftesbury had been the key mover against the street party, adding that there were only two more formal complaints.
Shaftesbury uses Four Communications for public affairs, but the agency said it had not been involved in this campaign.
Threepipe, which handles consumer PR and media relations, was unable to provide more information on the lobbying drive.
'Camden's decision is mainly a response to opposition from Shaftesbury. They have caved into corporate lobbying,' said Smith.
But the council disputed this assertion. A spokeswoman confirmed the council had received objections from three organisations - Shaftesbury, the Covent Garden Community Association, and Matthew De Giles, from the Rio Beach clothing shop.
She stressed that Shaftesbury 'has an interest in some 120 businesses in the area' and that De Giles had 'contacted a number of businesses in the Earlham Street area'. She added: 'In addition, we received a number of concerns from individuals who wished not to be named.'
Republic will fight the decision by Camden Council, which had previously accepted its event management plan.
The council spokeswoman said Republic had rejected an offer to apply for its event to be held at Lincoln's Inn Fields, 'the largest public open space in the Covent Garden area'.