A £26 million high street redevelopment has finally been given the green light - after proposals were agreed to take sewage away from the site in tankers.

The radical solution for the planned transformation of the former Nasons department store in Canterbury has been devised to avoid adding to water pollution at Stodmarsh nature reserve.

The problem has stalled the scheme for almost three years. But now it has been agreed that effluent from the development can be pre-treated in an on-site tank before being removed and disposed of away from the River Stour catchment, with predicted twice-daily collections.

The breakthrough means that work on the derelict, boarded-up High Street site can finally begin, with the project described as a "huge shot in the arm" for Canterbury's retail sector. There will be a new pedestrian retail arcade, a covered market hall, offices and 33 flats and 32 serviced apartments - together called Biggleston Yard.

There was optimism when the ambitious redevelopment proposals for Nasons were first revealed in 2019 and met with widespread praise.

However, the plans hit the buffers when, like many residential schemes across the Canterbury and Ashford districts, Natural England halted large scale housing developments. It said projects could only go-ahead if they offered acceptable remedies to prevent high levels of nitrogen and phosphorous entering the River Stour, which causes excessive algae growth.

The solution for Nasons has been thrashed out between Natural England, the city council and the developer. This has now led to planning permission for the scheme being approved, subject to numerous conditions.

In other housing schemes, developers may have to pay "nutrient credits" to help fund protected wetlands and other environmental benefits to gain planning permission.

City council leader Ben Fitter-Harding says being able to grant approval for the Nasons plans is "brilliant news" for Canterbury.

"It is a huge shot in the arm for our retail sector which, like most, is struggling in the aftermath of the Covid lockdown," he said.

He credits detailed work between the three parties for securing sufficient mitigation to allow the "crucial" development for the city to proceed.

"I know residents, visitors and businesses alike will be as thrilled as I am that we've passed this important milestone," he added.

The Nasons family department store closed in September 2018 and was followed by Debenhams opposite in January 2020, ripping the retail heart out of Canterbury.

The Nasons site is owned by London-based property investor and development company the Setha Group, which is working closely with award-winning architects Child Graddon Lewis and Clague.

They have rebranded it Biggleston Yard in recognition of the one-acre location's historical connections.

On the site is a mid-19th century foundry used by HM Biggleston & Sons - a six-generation family business that produced iron castings, railway girders, lamp-posts and other street furniture. The foundry is to be retained and refurbished, and the forge repurposed and integrated within the scheme.

The architects, who are not currently commenting on the breakthrough, previously claimed the development will be an exciting, new retail destination, and a place to live and stay in the heart of Canterbury.

No timeframe has yet been given on when work will start or when the development is expected to be complete.

But there are hopes the waste treatment works and tankers may not be needed at all in the future if alternative ways of safeguarding the Stodmarsh nature reserve are developed.

Meanwhile, the redevelopment of the former Debenhams site - which includes 74 flats and retail space - remains stalled. The council and developer are said to be continuing to work on a solution for the scheme.

The project also suffered another setback in January when a retail operator called 15:17 ran into financial difficulties and pulled out of taking a lease.