This would see 750 of the 1,500 Treasury jobs relocate from London in a sea change in the way the Whitehall Department works.
Further details of the proposals have now emerged, with a site at Teesside public airport now the most likely location.
Details of the ambitious campus plans proposed as part of a bid by Tees Valley Combined Authority include a moat and multi-story offices to house senior officials.
The decision to bring officials to Teesside would be a coup for Tees Valley Conservative mayor Ben Houchen.
Mr Houchen argued that the Conservative government should look away from major northern cities such as Leeds and Manchester.
But it would also be a blow to Middlesbrough Mayor Andy Preston, who said the city would be the ‘best place in the world’ for the new base.
The site’s strong air and rail links near Darlington, including a recently re-established direct service to Heathrow, have likely increased the chances of the airport site.
The specific area of the affected airport land has not yet been revealed.
Work began in March to develop a £ 200million business park at the airport on the south side, with 3.4 square meters of logistics, industrial and commercial space.
No official confirmation has yet been made by the government on the move.
It was hoped that the Chancellor would confirm the decision in the November budget, but that has now been postponed due to the coronavirus pandemic.
Mr Houchen said: “I have had many conversations with ministers about moving departments north, and I made it clear that these jobs should come to Teesside.
“The Treasury just can’t move to Leeds or Manchester. Big cities do not face the same challenges and problems that face our towns and villages across the country.
“The majority of Britons don’t live in cities and if the government is serious about making sure that policymakers understand the needs and challenges of communities outside of London, they cannot just move these jobs to another metropolitan city. .
“A move to Teesside will provide a level of education for public officials on the real needs of people across the UK – many of whom voted Conservative for the first time in 2019.”
Richmond MP Sunak brought nine treasury officials to the region earlier this year ahead of his promotion to chancellor.
He reportedly said he wanted to see senior officials at the base on a regular basis.
Mr Sunak, whose North Yorkshire constituency includes Stokesley and Great Ayton, has established close ties with other Teesside Tories, including the former Northern Powerhouse minister and Middlesbrough South and East Cleveland MP Simon Clarke.
He was among the first to propose Teesside as a potential location for a free port.
Mr Sunak was involved in the South Tees Development Corporation and its attempts to regenerate the Redcar steelworks while he was Chief Secretary to the Treasury.
The move is an attempt by the Tories to strengthen the party’s grip on Teesside after winning ‘red wall’ seats in areas such as Labor’s Sedgefield, Redcar and Darlington in the election last December.
Mr Houchen added: “There is no clearer way for the government to show that it is serious about the top leveling program than to move the government from London to Teesside.
“Too often we see that the North, for many, means Manchester.
“No one would believe the government is making any real attempt at leveling if it just wanted to move departments from England’s largest city to England’s second largest city. ”
Ahead of the last election, Labor also said they would break up the Treasury and move parts of the department north.
On Saturday, Cabinet Minister Michael Gove selected Middlesbrough and Teesside as potential locations for public service jobs.
He suggested that the government’s so-called “leveling” program will see departments leave the capital.