This is the full text of the resignation letter sent by former energy and climate change secretary Chris Huhne to Deputy Prime Minister Nick Clegg, and Mr Clegg's reply:
I am writing to resign, with great regret, as Energy and Climate Change Secretary. I will defend myself robustly in the courts against the charges that the Crown Prosecution Service has decided to press. I have concluded that it would be distracting both to my trial defence and to my official duties if I were to continue in office as a minister.
It has been a privilege to serve with you in the first group of Liberal ministers in a British government since 1945. As Liberal Democrats in government, we have put the national interest first. When we negotiated the coalition agreement, Greece had been hit by financial crisis. Since then, Portugal, Ireland, Spain and Italy have all been hit, vindicating our decision to tackle our own bigger budget deficit. We have had an essential role in ensuring that those decisions are fair. Our decisions are putting in place the foundations for a long-lasting recovery, a rebalancing of the economy, and durable jobs.
Our role in the coalition has ensured that growth in the green economy - already accounting for more than a million jobs - will be a large part of the solution. We have legislated in the first Energy Act 2011 for the pioneering pay-as-you-save Green Deal which will revolutionise our energy saving efforts, provide jobs across the country, and save householders money. The white paper on Electricity Market Reform has mapped out a new policy to encourage the billions of investment that we need in all three families of low carbon electricity generation - renewables, nuclear and clean coal and gas. The Green Investment Bank will support this goal, and this will also create new industries in which the UK will have a head start.
We have put consumers' interests - today and in the long term - at the heart of our policy, encouraging more competitors in the electricity and gas markets, working with Ofgem to simplify the confusion of tariffs, and getting tough on abuses.
I am proud that the UK has played a leading role in the revival of international climate change talks through the United Nations at Cancun and Durban. Climate change is an area where working with our European partners can help us to achieve national goals which would be out of reach if we were isolated and alone.
The Liberal Democrats under your leadership are playing an essential role in ensuring that the coalition government reflects liberal values at home and abroad. I have been proud to help put our commitments to freedom, fairness and the environment into practice, and to demonstrate once again that liberalism is alive and well in the country of its birth.
This is the full text of the letter sent by Mr Clegg after receiving Mr Huhne's letter of resignation:
Thank you for your letter.
I am immensely grateful for the huge contribution you have made to the government over the past 18 months; both in the trailblazing work you have undertaken as Energy and Climate Change Secretary and in your wider role in government as a key architect of the coalition.
You have shown real leadership in your time at DECC (the Department of Energy and Climate Change), driving forward a key part of the government's agenda tackling the challenges of climate change and driving green growth and jobs. The Green Deal and other major initiatives that you pioneered will deliver major dividends to the public while marking a major step change in the UK's approach to the environment.
I fully understand your decision to stand down from government in order to clear your name but I hope you will be able to do so rapidly so that you can return to play a key role in government as soon as possible.
Here is the full text of Deputy Prime Minister Nick Clegg's statement following the resignation of Chris Huhne.
"Good morning everybody.
"I totally understand and respect why Chris Huhne has stood down from his position in Government to clear his name.
"Chris Huhne is a good friend and a close colleague and I think he has done an outstanding job as secretary of state for energy and climate change.
"He has been really a pioneer in new, ground-breaking policies which I believe will stand the test of time.
"If he clears his name, as he wishes to, I have made it clear to him that I would like to see him back in Government in a key position.
"I am pleased that Ed Davey has agreed to take up the post as the new Secretary of State for Energy and Climate Change .
"Ed has a lifelong commitment to the environment, to green issues.
"He has shown as a minister a formidable grasp of the details of Government policy.
"I think he is the right man for the job to take up from where Chris has left off to provide sustainable solutions to the long-term energy needs of this country.
"I will be meeting Ed shortly so that he can make an early start in that very important work.
"Thanks very much."