West Cumbrian councillor Tim Knowles quit his post as member for Transport and Environment on Cumbria County Council's cabinet.
Cllr Knowles said it 'was a matter of principle' that meant he could not continue in his role on the cabinet.
Last week county Councillors decided west Cumbria would not have high level nuclear waste buried below its surface. Cllr Knowles had tabled a motion to look for a site but excluding the National Park.
In his resignation speech Cllr Knowles hit out at Leader Eddie Martin. Speaking exclusively to ITV afterwards he gave his reasons for leaving:
Since last weeks decision there have been allegations that Conservative councillors in the cabinet were instructed to vote NO by Leader Eddie Martin.
Cllr Knowles said during the cabinet meeting there had seemed to be inconsistencies between what councillors said and how they voted.
But the allegations were denied by the leader.
Cumbria County Council's vote against the nuclear repository was raised in the House of Lords this morning by Lord Jenkin of Roding .
He was worried that the councillors could have had pressure put on them to vote no, because of an email sent out by an anti nuclear campaigner.
Minister for Energy and Climate Change Baroness Verma said she would look into the allegations.
So as the fall out continues from last weeks decision, one councillor leaves his executive post and investigations are launched into whether intimidation was a factor is the decision last week.