Property investor Delancey, which entered into a partnership with Portsmouth City Council in 2019, has confirmed the collaboration has ended - leaving a question mark over proposals for the north of the city.
The group owns a long leasehold of the former Tricorn site - now the Market Way car park - which was earmarked for re-development as part of a scheme as far back as 2004, previously known as the Northern Quarter and City Centre North projects.
City council leader, Councillor Gerald Vernon-Jackson, believed this actually meant work could progress more quickly.
'The council for a long time has been trying to rebuild the city centre - or the northern quarter - with Delancey,' he said.
'They have been very slow about bringing forward plans and now they have now said they are going to walk away.
'So this is really good news. We are hoping they will sell the site to us.
'Councils shouldn't always get involved with large development schemes but where the private sector has failed for more than 15 years we need to step in and make this happen.'
It comes after the council bought the Sainsbury's site on Commercial Road this year to use the land as part of the regeneration, which includes creating a new road into the city alongside the existing road out in Hope Street.
Cllr Vernon-Jackson added: 'We own almost everything north of that part of the A3. That means we have somewhere where we can start development and get something moving on the site.
'We would use the site for a mix of residential, commercial, retail and restaurants.'
But former council leader and Portsmouth Conservative boss, Cllr Donna Jones, claimed it was a 'backwards' step.
She previously told The News her group had set aside £15m to re-develop the city centre when in power.
Cllr Jones said: 'The Libs Dems failed for 10 years to build the northern quarter then again in the last three years. And now they have not just failed to move forward, they have taken it backwards. Delancey is a key player.
'If the leader says he wants to acquire the Delancey land and develop a regeneration project on his own, how is he going to pay for it - how are the taxpayers going to pay for it? The people of Portsmouth deserve better and this could be the end for Commercial Road.'
Her deputy, Cllr Luke Stubbs, added: 'At the end of the day Delancey will be looking to make a profit so it'll probably be the case that the land will make the most money if used for tower block housing rather than what the council wants to do.'
But Cllr Vernon-Jackson said it would be possible to borrow the money required and he was confident Delancey would 'step aside' from the project.
In 2019 the administration claimed the partnership would 'de-risk' the city centre scheme by having the backing of a private company.
Labour councillor Cal Corkery said: 'The Labour group raised concerns about the partner venture with Delancey back in 2019 before it was decided.
'Delancey is exactly the same developer for the failed Northern Quarter project. I could not see any good reason why it would be different this time.
'The council is still the freeholder of the site. If Delancey isn't going to do something with the land soon the council should move towards a compulsory purchase order of the land.'
Cllr Vernon-Jackson added that a compulsory purchase order was considered in 2007, but had not been possible.
A spokeswoman for Delancey said the pandemic was a 'significant factor' in causing delays.
'As a proposed partnership, we certainly looked at a few different options for the site, however, during this period other more immediate projects have been prioritised by Portsmouth City Council as part of their overall plans to improve the city centre,' she said.
'As the country comes out of lockdown and people return to the city centre we will look at options for the site to maximise the assets long term interests.'
Delancey would not comment on how much they had spent on plans since 2019.
In 2017 it was reported that the council had submitted a £25m bid to the Solent Local Enterprise Partnership (LEP) for the City Centre North scheme.
The LEP confirmed the funding application from the council was withdrawn in October 2019.
History of the failed city centre regeneration project
LOVE it or hate it, the Tricorn Centre - that once stood where the NCP Market Way car park now is - was a prominent landmark in Portsmouth.
The Brutalist structure, which was part shopping centre, nightclub and car park, was demolished in 2004 after it gradually fell out of use.
Following its demolition the city was left with an empty plot of land at its centre.
Since then numerous schemes have been mooted, starting with the Northern Quarter visualisation when developer Centros won planning permission for a scheme valued at £500m in 2005.
The Northern Quarter project would have involved the demolition of dozens of properties in the area to make way for new shops, a leisure hub and housing.
But by 2016 nothing had happened and Portsmouth City Council formally agreed to end the deal with hopes of creating a new scheme with the land owner.
Property investors Delancey were introduced to the project as the authority said it would work with them to create a new outdoor shopping village on the site.
Council leader at the time, Councillor Donna Jones, said the original Northern Quarter proposals fell through when the recession hit in 2008.
So in 2017 a new scheme was made public - re-branded as City Centre North.
The main purpose of the project, which was expected to cost around £60m, was to turn Hope Street and Flathouse Road into a dual carriageway to help funnel both northbound and southbound traffic quicker through Portsmouth - something that the council has said it is still looking to do now.
Alongside this, both Market Way and Church Street roundabouts would have been replaced by traffic signal junctions, with a new public square or marketplace developed at the top of Commercial Road.
Since no progress seemed to be made with this scheme either, in 2019 the council announced it would be officially partnering with Delancey to bring forward the regeneration of the city centre.
And it is this partnership that has now ended.