Recent H I observations of the M 81 group made with the Very Large Array (VLA) (Yun 1992; Yun et al. 1993) have revealed a previously unknown structure: a long 'bridge' of gas stretching from NGC 3077 towards the northwest. In a previous paper (Thomasson & Donner 1993), we presented a model of the tidal interaction between M 81 and NGC 3077, aimed at explaining the spiral pattern in M81 and the ... [Show full abstract] long known bridge of gas between the two galaxes. We now show that if our previous model is supplemented by an additional large disc of gas belonging to M 81 (in agreement with Yun et al.'s observations), a narrow gaseous feature forms in the gravitational wake behind NGC 3077. This feature closely resembles the bridge observed by Yun et al. Our model of the bridge, as opposed to e.g. tidal or ram pressure stripping models, does not require that NGC 3077 once possessed a gas disc.