Unions now plan a 48 hour walkout in May - but when asked by the ECHO what contingency plans there were to keep the tunnels open Mr Scales said he would have no option but to close them.
In a statement released to the ECHO, Mr Scales, said: "These questions are premature as we have received no notification of any further strike action. I must, however, stress once again that if we cannot operate the tunnels in a safe manner we have no option but to close them."
Despite being asked for his response, Mr Scales could find no words of comfort for small business owners who said they stood to lose thousands of pounds in lost income because of the strike action.