Sky News has learnt that TalkTalk will publicly announce the move on Wednesday alongside its interim results.
The decision to shift its head office to the Soapworks development in Salford Quays, which was communicated to staff on Tuesday afternoon, will make TalkTalk one of the most prominent British companies to axe a London HQ in favour of another major city.
In recent years, businesses including BT Group and Tesco have outlined plans to shed long-standing headquarters as part of more widespread corporate revamps, with the former still to announce details of its new base.
TalkTalk already has a significant presence at the Soapworks site, with the bulk of its workforce based there.
People close to the company said the decision to downgrade its London HQ to a satellite office would entail relocating hundreds of staff, with some additional recruitment activity expected to take place in Manchester next year.
TalkTalk currently employs approximately 500 people in London.
The company’s Soapworks office is close to the MediaCity UK development on the banks of the Manchester Ship Canal which has become a magnet for major employers including the BBC, Ericsson, ITV and Kellogg’s.
The public announcement will come alongside results underlining TalkTalk’s ongoing turnaround programme, with its shares down by almost a quarter during the last 12 months.
The company, which is run by its founder, the telecoms entrepreneur Sir Charles Dunstone, is also expected to confirm that a £1.5bn deal to accelerate the roll-out of fast broadband to millions of British homes has been abandoned amid a dispute with its prospective partner.
Sky News reported earlier this month that TalkTalk and Infracapital, an investment vehicle owned by the insurance giant Prudential, had reached an impasse after months of talks about a new joint venture.
Announced in February, the new independent company was designed to act as a new competitor in the race to deliver full-fibre communications to homes and businesses across the UK.
Under the plans, the ?JV was to be 80%-funded by Infracapital and 20%-funded by TalkTalk, which would also have provided a minimum volume commitment to the business by becoming a founding wholesale customer.
They set a target of reaching more than three million homes and businesses in mid-sized towns and cities.
TalkTalk is expected to pursue its ambitions to roll out a fast broadband network with another partner.
The move to develop such ventures forms part of a race to be at the forefront of the next phase of communications infrastructure amid growing government pressure on the private sector to deliver broadband capable of serving a modern digital economy.
Internet traffic is forecast to grow threefold between 2016 and 2021, illustrating the amount of capital being deployed to build out ultra-fast communications capabilities in Britain.
A TalkTalk spokesman declined to comment.