By Ian Walker 



  Costain Group PLC said Monday that it and National Grid PLC have agreed to terminate the contract for the upgrade to the power company's Peterborough and Huntingdon compressor stations. 


  Costain said that the contract experienced significant change and extra scope, which hit costs and scheduling times. 


  "Following detailed discussions between Costain and National Grid, both parties have mutually agreed to exit the contract and release Costain from its contractual obligations to complete the works," Costain said. 


  Costain shares at 0815 GMT were up 2 pence, or 3%, at 69.50 pence. 


  Write to Ian Walker at ian.walker@wsj.com