In consideration of the payment of an additional premium which is included in the premium hereon it is hereby agreed and declared that subject to the conditions of the Policy loss as insured by this Policy resulting from interruption of or interference with the business in consequence of damage (as within defined) to property at any electricity station or substation, gas work or water works of the Policy supply undertaking from which the Insured obtains electric current, gas or water shall be deemed to be loss resulting from damage to property used by the assured at the premises. Provided always that the insurers shall not be liable for any loss insured by this clause unless the failure of supply of electricity, gas or water exceeds as a period of 14 (fourteen) days and the liability of insurers under this clause shall only apply to such period in exceeds of 14 (fourteen) days.