Although teamwork is a leading innovation in work organization, detailed studies of employee responses, and the reasons for acceptance or rejection, are rare. Here, an advanced form of teamworking at a British aluminium smelter, part of a large Canadian multinational company, is examined. Direct supervision was abolished, and teamworking using semi-autonomous groups with job rotation, multiskilling and team briefing was introduced. Employees responded favourably to the initiative. Job satisfaction and labour productivity increased. Industrial action, overtime and accident rates fell. The conditions for this outcome included prior experience of job shedding, capital-intensive continuous process technology, union-management cooperation in the introduction of teams, and a pre-existing culture of strong work group solidarity. Some tensions remained, however, notably over the pay system and some aspects of work performance, and there was no evidence of a move towards high commitment.