Having posted earlier today about the Tunnel House Inn here are some directions for the mile walk to pub from the Thames Source.
From the stone at the Thames Source continue ahead below the bank (right).
Go through the gateway with a stile ahead to follow the field boundary (right) to a second gate where there is a ladderstile. After a third gate and ladderstile, the way is enclosed. On reaching a bridge over a dry canal do not cross but go left along the towpath.
Soon after running under the Kemble- Gloucester railway line, the path passes a round house. Follow the path under a road bridge to the Sapperton Tunnel.
The towpath ends in front of the Tunnel House Inn.