The culture secretary has ruled out privatising Channel 4 following a protracted review of its long-term future, but in return wants the state-owned broadcaster to relocate some or all of its operations outside London.

Karen Bradley will use a speech in Salford to announce that the new home of The Great British Bake Off will remain publicly owned, while increasing pressure for it to move large parts of its business from its existing headquarters.

The broadcaster welcomed the decision against privatisation, but said a major move would be “highly damaging to Channel 4’s business model and diminish our investment in the creative industries around the UK and our overall contribution to the UK economy”.

Tuesday’s decision marks the end of an 18-month ownership review that has strained relations between Channel 4 and the government. Bradley will say the broadcaster is a “precious public asset” that will continue to be “owned by the country”.

However, speaking at the Nations and Regions Media Conference, Bradley will announce the launch of another consultation on whether to move Channel 4 out of London to “serve the country” and spread creative jobs and opportunities throughout the UK.

Channel 4 has resisted the possibility of moving out of its £100m headquarters in Victoria, London, since the government floated potential relocation plans last summer, with cities such as Birmingham, Manchester and Leeds in the frame as potential new homes.

“We want the benefits of this national asset to be spread far and wide, not just in London,” Bradley is expected to say. “And that means rethinking where it is based and where it spends money.”

Channel 4’s chief executive, David Abraham, has previously said that a move would be costly and the best way to help the Midlands and other regions and nations in the UK was through commissioning programming out of London. He is to step down at the end of the year after seven years in post.

Bradley will say: “I am unsympathetic towards those who recoil in horror at the very idea of media jobs being based outside the capital. Or for those who insist that people with ideas in the West Midlands, West Country or west Wales must travel to Westminster to get their programmes made.”

The culture department, which is looking at a full move of the channel’s headquarters as well as just parts of its operation, estimates that fewer than 30 of the broadcaster’s 820 staff are based outside central London.

“A publicly owned broadcaster should have far more than 3% of its permanent staff outside London,” Bradley is expected to say. “We want Channel 4 to have a major presence outside London, stimulating creative and economic activity – including jobs – right across the country. Public assets should deliver for the public in every possible way. That is key to building an economy that works for everyone, not just a privileged few.”

Bradley is hoping that forcing Channel 4 to move will prove as successful as the BBC’s launch of a “northern powerhouse” in Salford, where BBC Sport and Radio 5 Live are based, and increasing its operations in the Midlands.

In September, the corporation said it would move half of BBC3, which became an online-only channel last year, to Birmingham in 2018. The UK’s second-largest city is also the home of a new youth team for BBC News and a base for its partnership with local newspapers.

Channel 4 has argued that with fewer than 1,000 employees it does not work at the the scale to warrant developing such operations, unlike the BBC, which employs 19,000 staff.

The new consultation, to be published in the coming weeks, will also look at whether Channel 4’s quota of original British commissions that must come from TV production companies outside London will be raised from 35% to 50%.

Channel 4 already exceeds its target, with more than half of original commissions in 2015 coming from outside the capital. Some of its big shows and series have been made in the north of England, not least long-running programmes such as Hollyoaks and Paul Abbott’s No Offence. Midlands-based Channel 4 shows have included a new Guy Martin series, Caitlin Moran’s Raised by Wolves, and My Kitchen Rules.

Bradley will make a ministerial statement to parliament on Thursday confirming the results of the 18-month review and announcing the new consultation.

The shadow culture secretary, Tom Watson, criticised Bradley for making the announcement in a speech before informing parliament. “Given your clear public commitment to come to the house first, I was surprised to hear that you are planning to make a speech outside parliament giving details about the future status of Channel 4,” he said in a letter to Bradley.