The Court of Appeal heard the unnamed solicitor said the council would remove business from barristers acting for Keith and Ann Gillingham.
The couple were appealing against being jailed for 28 days for contempt of court earlier this month after blocking a footpath near their home in Fawley, near Southampton.
Robin Belben, head of College Chambers, Southampton, said: 'On the face of it, it was an attempt to prevent Mr and Mrs Gillingham having access to justice. The three appeal court judges said the county council had been guilty of serious contempt of court.'
The council said: 'We apologised and assured the judge that the matter would be dealt with internally. The judges said there was no purpose to be served by taking the matter any further.'
The court released the Gillinghams following their appeal.