Paragraph 145 I1

Work in relation to which an estimate is submitted must not be commenced by Northern Powergrid until that estimate is agreed with the undertaker in writing and a purchase order up to the value of the approved estimate has been issued by the undertaker to Northern Powergrid and an easement for the routes of the apparatus has been granted to Northern Powergrid pursuant to paragraph 136(1) for the benefit of its statutory undertaking.