The Government has cancelled the tidal lagoon project in Swansea, with Greg Clark, secretary of state for business, saying: “The cost that would be incurred by consumers and taxpayers would be so much higher than alternative sources of low-carbon power that it would be irresponsible to enter into a contract with the provider.”

The tidal lagoon had previously received backing from Charles Hendry, a former energy minister, whose independent report stated: “I would strongly caution against ruling out tidal lagoons because of the hopes of other cheaper alternatives being available in the future.”

The National Federation of Builders (NFB) believes that the tidal lagoon project, featuring a U-shaped sea wall with turbines, would have been an important marker of change for the city and is disappointed at the Government’s decision.

As well as increasing the capacity of high skilled businesses operating in the south Wales region, the project would have aided the city to meet both its infrastructure and housing needs.

Guy Leach, chair of NFB Cymru, said: “It appears that Welsh efforts to become world leaders in tidal power have been overlooked for increased plane capacity for London and a nuclear power station that, over its lifetime, will produce half the power of Swansea’s tidal lagoon.

“This news is devastating for the region as well as our members. The tidal lagoon would have set a marker, not only for Wales for the rest of the UK.”