Cabinet Office minister Francis Maude is to step down from his post come May's general election, after four years spent driving the government's IT strategy.
The MP will not seek re-election in May, ending a 27-year career as a member of Parliament.
Maude has been instrumental in implementing the Coalition's digital strategy, helping set up Gov.uk, now the central government domain for 312 agencies and government organisation websites, as well as the cloud procurement framework G-Cloud.
In a letter announcing his intention to resign, Maude said the Cabinet Office saved 14.3 billion last year, compared to Labour's last year in office, as well as shrinking government property originally 26 times the size of Buckingham Palace.
He was also behind the creation of the Government Digital Service (GDS), Whitehall's coding arm responsible for driving digital public services.
Maude pointed out the initiative is now being copied in the US and Australia.
"I've worked closely with our brilliant Chancellor to drive these reforms, but there is much to do before the election and after to ensure that the reforms are irreversible," he added.
Industry trade body TechUK agreed with this assessment, while praising Maude's record in charge of the Cabinet Office.
Naureen Khan, associate director for central government, said: "Francis Maude's leadership has raised awareness of the importance of digital as a driver of efficiency across the public sector and under his direction we have seen some important initiatives, most notably the creation of GDS and a strong focus on opening up the public sector market to small businesses.
"We commend the minister's work to make the UK a global leader in cyber security.
"However, as the minister himself points out, there is still much to do. It is vital that the next government continues with the civil service reforms, and we are encouraged by the recent high profile appointments bringing in experienced leaders from the private sector, such as the new CEO of the civil service, John Mazoni, who must continue the reforms."
The government's digital strategy is aimed at improving the accessibility of public services, though Labour has criticised the Coalition for allegedly neglecting those without the skills to get online.
But TechMarketView analyst Georgina O'Toole acknowledged Maude's central role to the government's reforms.
She said: "There has been much good about what he has done. Government IT needed shaking up, on both the buy-side and the supply-side.
"Suppliers will be keen to know who will step into Maude's shoes to march forward with the agenda; his tenacity, and his unwavering commitment to changing government and supplier behaviours, will be hard to match."
However, she acknowledged that mixed views exist on his achievements, including his push to get rid of large suppliers seen as tying the government into long and expensive contracts, replacing them with SMBs.
She added: "There have also been decisions made that have been controversial. Both the sustainability of the savings and the longevity of the reforms have been called into question. Unfortunately Maude leaves before we have proof that the changes he has made will stand the test of time."
Maude spoke at the inaugural meeting of five digital governments, the D5 digital nations group, in December, to say the public sector can be too risk-averse.
He said: "Governments are very good at looking at new ideas and finding reasons not to do them.
"We must encourage people to experiment and take risks to find new and better ways of doing things, even if they don't always work. The greatest mistake is to never try anything new or to stick to something that doesn't work."
He suggested that public sector workers should adopt mantras associated with start-ups, like move fast and break things' and fail fast'.
