Avoncliff Aqueduct is a landmark on the canal route near the place where Milo Motion lost his keys. Its significance in the investigation is practical as well as geographical: the keys went into the water nearby, and Peter Diamond arranged for divers to search for them farther along the waterway, by the aqueduct.

The Waterway and Its Setting

Milo’s boat was moored above the Cross Guns at Avoncliff, on a stretch of canal before the aqueduct. After an evening meal and several beers at the pub, he returned to the boat alone; as he stumbled while opening its door, his keys slipped from his hand and fell over the side. He had spares, but the loss created a specific search problem for the investigation. The nearby waterway had an older character than the main canal. It had once carried barges transporting coal from the Somerset mines, and the stretch used for mooring was described as much narrower than the main canal, almost two centuries old, and edged with ancient flagstones. Where it joined the Kennet and Avon, an aluminum lift-bridge had replaced an older structure.

The Search for the Keys

The aqueduct became the next planned search location because the divers were asked to return the following day and look farther along the waterway, by Avoncliff Aqueduct, for Milo’s lost bunch of keys. The request followed Milo’s account of dropping them from the boat; the divers, already packing their van after earlier work, showed little enthusiasm for another assignment. The recovery mattered to the inquiry into Sid Towers’s murder aboard Milo’s boat. Peter Diamond considered whether Milo’s account of events could be trusted, including whether he had actually locked the boat before leaving. The keys’ loss and the planned dive therefore belonged not just to the landscape but to the practical examination of Milo’s movements and the boat’s security.

Bridge and Investigative Attention

As Diamond walked back along the towpath, the lift-bridge caught his attention. He studied its mechanism, reasoning that it had to be raised to let a narrowboat pass and noticing counterweights projecting from the fulcrum. He then pulled at the walkway and found it bolted down on the opposite side. With no boatyard traffic expected at that late hour, he left the mechanism unexplored and returned to the policeman on duty. The scene links the area’s physical details to Diamond’s investigative habits: an old canal route, a lost object beneath the water, and a modern bridge whose workings invite scrutiny. The account establishes the aqueduct as a point of reference for the planned search, while locating Milo’s actual mishap on the mooring stretch above the pub rather than asserting that the keys fell at the aqueduct itself.