I was reading a newspaper article about new Riverbuses being bought for London and it made me wonder why no other UK city has any significant cross city services? I know Cardiff has a very limited opperation and Manchester has a small water taxis and there are cross river short journey ferries, most famously between Liverpool and Wirral. Surely its a low infrastructure cost option for cities with a major river or canal? For instance Manchester and Salford have the River Irwell from outside Victoria Station which then turns into the Manchester Ship Canal which is next to / part of Salford Quays and runs next to the Trafford Centre. The Bridgewater Canal runs from Deansgate to Trafford Centre and Altrincham.