sentences:  In February 1967 the Grand Union Canal Society was formed, and later began campaigns to reopen both the Slough Arm and the Wendover Arm.The initial plan failed due to a lack of local interest, and because the legal position was not sufficiently strong to mount a successful campaign.In 1979 the Grand Union Canal Society was worried that nature conservation lobbying might lead to the arm being closed to boats completely, so it organised a campaign cruise to Little Tringford Pumping Station, the head of navigation at the time.