Sajid Javid has resigned as Chancellor of the Exchequer just weeks ahead of what has been touted as one of the greenest budgets in history, following an explosive power struggle with Number 10. He is to be replaced by former Chief Secretary to the Treasury Rishi Sunak, who now faces the task of leading the development of the government's net zero spending plans.

Javid stepped down following a row with Boris Johnson, which saw the Prime Minister reportedly demand that the Chancellor sack all his advisors and sign up to a new joint team of advisors shared between Numbers 10 and 11 Downing Street. Javid opted to resign in protest, rather than accept the ultimatum.

A spokesman for Javid said "no self-respecting minister would accept those terms", according to the Press Association.

Shortly after Javid's resignation, Number 10 confirmed it has appointed Sunak as his replacement, making him the second most influential member of the government behind the Prime Minister, Boris Johnson. 

The Rt Hon Rishi Sunak MP @RishiSunak has been appointed Chancellor of the Exchequer @HMTreasury pic.twitter.com/OTYOkujnbo

— UK Prime Minister (@10DowningStreet) February 13, 2020

The shock move follows reports of tensions between Javid and Johnson's top advisor Dominic Cummings, who is know to have clashed repeatedly with Number 11 and pushed against Treasury spending contraints.

Javid's resignations makes him the shortest serving Chancellor in half a century, having led the Treasury for less than seven months since Boris Johnson first became Prime Minister last year.

Sunak, who was appointed to the Treasury team under Javid last July, is now set to play a critical role in the government's net zero and environmental strategy.

His predecessor had promised to prioritise the environment and the net zero transition in next month's Budget, which is scheduled for 11 March, and the Treasury is also set to undertake a major review of the potential costs for transitioning the UK economy to net zero by 2050.

Recent reports have suggested the Treasury is considering new incentives for green building upgrades, increased energy efficiency funding, extended grants for plug in vehicles, and support for new nuclear plants and industrial carbon capture projects alongside this week's confirmation of new funding for electric buses and cycling infrastructure, as the government looks to accelerate the rate of decarbonisation ahead of this year's crucial COP26 Summit in Glasgow.

However, the Treasury could also anger environmentalists at the upcoming Budget with its plans to review Air Passenger Duty. 

First elected as MP for Richmond, Yorkshire, in 2015, Sunak previously worked for investment bank Goldman Sachs, and has also worked for several hedge funds. He served on the Environment, Food and Rural Affairs Select Committee from 2015 to 2017.

The shock developments came just an hour after Johnson axed Business Secretary Andrea Leadsom and Environment Secretary Theresa Villiers, alongside a number of junior Ministers.

In an afternoon of fast moving developments, Number 10 announced that International Development Secretary Alok Sharma had been promoted to replace Leadsom as Business Secretary and will also be "Minister for COP26".