This paper describes the substantial potential of tidal barrage solutions for renewable energy generation in the UK. It demonstrates that installations on as few as eight major estuaries should be capable of meeting at least 10% of present electricity demand, and possibly significantly more, employing fully proven technology. This should be achievable, under favourable UK Treasury discount rates, at unit electricity prices that are likely to be competitive against future costs of alternative sources. This potential substantially exceeds that of ‘tidal stream’ turbine or practicable ‘lagoon’ systems, much vaunted in recent times. It also draws attention to a recent study investigating the tidal power potential in the north-west of England.