With no design and no drawings, they began with only a mental image of what they wanted. Their first idea was to build a superstructure from whatever materials they could find. They wanted a tower to provide them with a raised entrance lobby, keeping the lower decks private and providing an excellent place to mount a wind generator.

The arrangement inside was still anyone’s guess. From the tower, a spiral staircase - if they could find one - would lead down through the boat to the two decks below. In the hull, three bedrooms were planned with a family bathroom in which Chris hoped to put a composting toilet and recycled water system.

Upstairs was to be one single, long, open plan living room. Every window and door relied on whatever Chris could find second hand. In the kitchen area they planned a wood burning stove to cook on and to provide hot water and heating, but only if they could reclaim one from somewhere.

The whole build was a list of ifs and maybes. The reliance solely on reclaimed materials means you have little control over the design, schedule, or cost. Chris and Sze had just £50,000 to build their houseboat, £20,000 of which was set aside for the eco features. It was a ridiculously tight budget and nobody knew what would happen.

But because it’s a houseboat they could do pretty much what they liked.