Two of the UK's oldest nuclear power stations are to remain in use until at least 2023, EDF Energy has announced.
Hinkley Point B near Bridgwater in Somerset and Hunterston B in North Ayrshire started generation in 1976 but have now been given seven-year extensions to their existing decommissioning dates in 2016.
Extending the life of the stations is good news for more than 1,500 staff and contractors at the two plants, while they will continue to generate enough low carbon electricity for around two million homes.
EDF's decision, which follows work with the independent nuclear regulator, comes amid reports that Chancellor George Osborne will announce plans for up to 30 gas-fired power stations in this week's autumn statement.
EDF has eight nuclear power stations in the UK, with the newest being Sizewell B following its opening in 1995.
The company is currently working on plans to build a new power station at the Hinkley Point site.
In 2010, five year extensions were granted to the Heysham 1 and Hartlepool stations, taking their likely decommissioning date to 2019.
Chief executive Vincent de Rivaz said: "This decision will provide low carbon energy to keep the lights on in the UK and it will safeguard jobs at the plants, in the UK nuclear industry and its supply chain.
"It follows a thorough review of safety over the lifetime of each of the plants."
He added that extending the plants' lives also brought training and employment opportunities for a new generation of nuclear engineers and operators.
Hinkley Point B and Hunterston B operate at approximately 70 per cent load due to boiler temperature restrictions.
British Gas owner Centrica has a 20 per cent stake in EDF's eight plants and in the project carrying out pre-development work for new build stations.
Alongside the life extension announcement, EDF has also re-opened its visitor centre for Hinkley Point B in nearby Bridgwater town centre.
The Scottish government is opposed to new nuclear power stations and can effectively veto any UK government plan to build more north of the border.
The SNP administration wants to phase out nuclear but is not opposed to extending the life of existing stations while making a push for renewable energy to cover the country's electricity needs.
A Scottish government spokeswoman said: "We have consistently made it clear that nuclear energy will be phased out in Scotland over time, with no new nuclear build taking place in Scotland.
"But we have also consistently made clear that this does not preclude extending the operating life of Scotland's existing nuclear stations to help maintain security of supply over the next decade while the transition to renewables and cleaner thermal generation takes place.
"Subject to the relevant safety cases being made, the Scottish government would not oppose operating life extension applications at Torness and Hunterston.
"Scottish government policy is against new nuclear build."
SNP, Liberal Democrat and Green MSPs voted in 2008 to oppose new-build nuclear stations.
Patrick Harvie MSP, Scottish Green Party co-convener, said: "Scotland doesn't need to sweat its nuclear assets to keep the lights on.
"This extension shows how light touch regulation is failing us and the Scottish government shouldn't just wave it through.
"The Scottish Parliament has voted against new nuclear, and it's clear our renewables targets are achievable.
Why on earth would we allow EDF to increase our toxic waste legacy and continue the risks of running a plant built in the 60s?"
Dan Barlow, of environmental group WWF Scotland, said: "Nuclear power is the ultimate unsustainable form of energy so it is disappointing that EDF Energy has been granted approval by the UK government to extend the life of Hunterston."