At a heated meeting yesterday, members of the authority unanimously backed a call for a judicial review into the decision to axe 62 branches in the county.
Councillors say the Post Office has failed to take into account unique issues which face Cornwall and say the current consultation is flawed.
If a review is granted and the High Court sides with Cornwall County Council, it would deal a bitter blow to the Government and Post Office Ltd – possibly even forcing the plans to be shelved.
“This consultation period is a joke,” said executive member of Cornwall County Council, Eric Brooke.
“The Post Office is asking for feedback during the summer, when Cornwall is busy hosting millions of tourists, and when many of our councils do not have meetings. They also appear to have a complete lack of understanding of the issue of rural poverty and they are using census data from 2001.”
Roger Jones, chairman of the community policy development and scrutiny committee, which called for the review, condemned the consultation process as “flawed”.
He said it was essential that the council took urgent action to prevent some rural villages being left with no amenities at all.
This, he said, would create serious problems for elderly people and those without transport.
Angry councillors from across the county condemned the Post Office proposals to close 49 branches and replace a further 13 by outreach services in Cornwall.
Many criticised the timing of the consultation process, arguing that it would be almost impossible to carry out a comprehensive consultation exercise during the summer months, when many people were on holiday and councils were in summer recess.
Others pointed out that while the criteria used by the Post Office identified the issue of urban deprivation, it failed to take rural poverty into account.
Many Cornish communities have already stepped up to the mark and launched campaigns to save their local branches before the consultation period closes at the end of August.
More than 250 people attended meetings in West Cornwall at the weekend to protest at post offices in villages around Falmouth and Redruth being shut. Julia Goldsworthy, the MP for Falmouth and Camborne, has also called for people to write letters to Post Office Ltd as well as sign petitions.
On Saturday, 75 people marched from St Breward to St Tudy, on Bodmin Moor, to demonstrate the strength of feeling about rural post offices.
A spokesman for Post Office Ltd said all comments made during the consultation period would be taken into account.
Moreover, she added that it was the same period for Cornwall as everywhere else in the UK.
“We will be taking all the feedback on board and attending as many of the meetings as we can during the consultation period.
“The consultation will last six weeks. No-one is off on holiday for that long so we should be able to talk to all the relevant people.”
The spokesman added that officials were looking forward to meeting local people “face to face”.
A spokesman for the Department of Business, which ordered the closure of 2,500 post office branches nationally, said it had not yet received any information from Cornwall County Council about a judicial review.
“We would not comment on any ongoing legal issues,” she added.
Yesterday, the WMN reported that Postwatch, which advises the Government on post office services, had declared as “unsatisfactory” aspects of the consultation on plans to close up to 45 branches in Devon.
It is understood that around eight of those originally earmarked will win a reprieve, although a new branch has been added to the list of closures.