Newcastle United are looking at a complete rebuild of St James’ Park, rather than just an expansion, as part of a major redevelopment of the surrounding area that would bring far more than a new football stadium.

Although there has long been a desire to expand St James’ Park, the proposal being considered is far more ambitious and would involve the construction of a purpose-built, state-of-the-art stadium on the existing location.

Telegraph Sport can reveal for the first time that should Newcastle decide to stay at St James’ Park, rather than move to a new site, which remains under consideration, the project is far grander than initially thought.

Rather than add additional seats, the idea would be to completely reconstruct the stadium, not merely rebuild, expand and modernise the Gallowgate End and East Stand. The estimated cost of the new scheme could be as high as £1 billion as capacity could be expanded to 65,000-70,000.

It is believed that whatever the final decision, which is expected to be made public early next year, the new stadium will be a state-of-the-art, multi-purpose venue at the heart of a redeveloped city centre.

It is thought that should Newcastle elect to stay at St James’ Park, and the council extends their lease, which only has 70 years remaining, the stadium could be moved away from the Grade A-listed buildings behind the East Stand to create more space.

That would require the demolition of a multi-story car park in the corner behind the Milburn Stand and Leazes End. It would also require the realignment and reconstruction of Barrack Road, a busy thoroughfare in the heart of the city.

A reimagined St James’ Park would be comparable to Tottenham Hotspur’s White Hart Lane project.

However, Telegraph Sport can also reveal that although there have been plenty of internal discussions about a new stadium and the options available should they move, the council, which would have to grant planning permission, has not been involved, so the construction phase of the project is still a long way off.

The council’s view appears to be particularly significant given fresh impetus has been given to another possibility this week, initially revealed by Telegraph Sport earlier this year: the building of a new purpose-built stadium behind the current stadium, on the site of the Victorian-era Leazes Park.

Leazes Park is in a conservation area and it would be controversial to build on a historically significant green space, in the heart of the city.

That the club have had no discussions with the council about this option appears odd given that they would need to know if the city were willing to at least consider allowing them to build there.

Newcastle, though, have stressed that whatever decision they make, they intend to stay in the city centre rather than move out of town in search of more space.

As one source said: “We are going to stay in the city [as] we know how much the location means to Newcastle United and its supporters.”

A spokesman for Newcastle Council said: “There has been much speculation in the media about the future of St James’ Park.

“While there have been no formal talks between the club and the council, our door remains open as it would with any developer. When the club wants to sit down with us, we will listen and advise.”

Given that Leazes Park and its surrounding area are protected, there is bound to be opposition to any proposal to build there, although the club could offer to build a new park area as part of a far larger redevelopment of this part of the city centre.

There is some space to expand behind the Leazes End, but getting permission to build here could be necessary, even if Newcastle stay at their current St James’ Park site.

Until the council is consulted, it is not known what sort of planning permission they would be willing to grant, which means the process could be further delayed when those talks take place.

Newcastle United have stressed that a final decision is yet to be made and all options remain on the table.

Saudi Arabia’s Public Investment Fund has revealed a plan that promises the best economic return, in terms of match-day revenues and as a multi-purpose venue able to host other large events.

The club have also pledged that supporters will be consulted before a final proposal is made to the city council.

The next stage of the “once-in-a-generation” project is expected to be announced early next year, but that may be a public consultation, with the two potential proposals shared with the council and supporters.