Nuclear chiefs have admitted there will be a one-year delay in production of the first power from a proposed new plant.

NuGen - the consortium behind plans for the Moorisde facility on land next to Sellafield - have previously stated that the first of the three reactors would be operational by 2024.

However, documents released to the public for the first time this week show that the first AP1000 reactor is now not expected to produce power until the end of 2015.

Campaign group Cumbrians Opposed to a Radioactive Environment (Core) claims the delay is NuGen's "belated realisation that its original timetable was just pie in the sky". 

NuGen responds however that the start date was planned many years in advance and the newly-announced date change is due to elements "out of its control".

The plans - on which the public is currently being consulted - are due to be submitted, says NuGen, for final financial and planning approval in 2018, with construction due to start two years later.

Core spokesman Martin Forwood said: "The delay will wreak havoc with the timetable for building the second and third reactor; the latter originally scheduled for completion by 2026.

"The timeline is slowly but surely marching backwards and West Cumbria need to wake up to that reality."

Mr Forwood added that NuGen's plans - including associated road, rail and accommodation projects across West Cumbria - are "staggering in scope". He added: "The period of major disruption and sheer misery caused to many locals by these combined works will now be extended."

A NuGen spokesman said: "The Moorside project is still in the development phase and we remain on track to achieve the final investment decision in 2018. 

"Beyond that, there are elements of the project which are out of our control and NuGen believes it is more appropriate to refer to the target date for Moorside site delivering power as the mid-2020s."