For more than 160 years, Colman's Mustard was synonymous with the city of Norwich.

That link may have now been broken - with production of the condiment switching to the Midlands in 2020 - but a strong flavour will remain, after a series of sites linked to the company were given special heritage protection by the government.

The Department for Digital, Culture, Media and Sport has granted listed status to a number of locations in Carrow and Trowse where, in the company's heyday, thousands of people worked at its sprawling complex.

It comes after experts from Historic England carried out an investigation of the buildings at the request of Norwich City Council.

The authority wanted a survey of heritage sites in the area before much of it is regenerated as part of a huge £653m development, known as the East Norwich Masterplan.

Eastern Daily Press: Colman's employees making and filling mustard tins at the Carrow Works site in Norwich. Date: circa 1940.Colman's employees making and filling mustard tins at the Carrow Works site in Norwich. Date: circa 1940. (Image: UNILEVER ARCHIVE)

Among the locations to be given a new conservation status is the conservatory at Carrow House, off Bracondale, which was once home to the Colman family. It has been newly listed at Grade II*.

Eastern Daily Press: The Conservatory at Carrow House.The Conservatory at Carrow House. (Image: Archant)

The conservatory, with ornate patterns in ironwork, stained glass and mosaic, was built in 1895.

Eastern Daily Press: Carrow House.Carrow House. (Image: PA Media)

Carrow House, already listed at Grade II in 1986, has had new information added to the list entry to give more detail - including on two ornate iron gates and, in the centre of its garden, a circular pond edged in stone.

Eastern Daily Press: The gardens at Carrow House and Conservatory.The gardens at Carrow House and Conservatory. (Image: PA Media)

Jeremiah James Colman extensively rebuilt the mid-19th century villa between 1860 and 1861.

Eastern Daily Press: Jeremiah James Colman.Jeremiah James Colman. (Image: Archant)

Other sites linked to industry in the same area of the city have been newly listed at Grade II.

They are the former Trowse railway station, the late 19th century engine house at Trowse sewage pumping station and its early 20th century replacement.

The now-closed Trowse station, built between 1844 and 1845, was crafted from knapped flint and was used by Colman's.

Shut during the Second World War, it reopened briefly in the 1980s, during work on Norwich Railway Station.

The sewage works at Trowse were built to improve social conditions in around 1869 by the Norwich Corporation.

They were constructed in response to the growing problems of sewage disposal caused by the rapid development of the area, generated by the development of the mustard factory.

Eastern Daily Press: Trowse Sewage Pumping Station.Trowse Sewage Pumping Station. (Image: PA Media)

Two engine houses, one built around 1869 and its replacement, built in 1909, are both newly listed at Grade II.

Eastern Daily Press: The former bottle kiln at the Deal Ground in Trowse.The former bottle kiln at the Deal Ground in Trowse. (Image: Archant)

Further information has been added to the Grade II listing for the timber drying bottle kiln at the nearby Deal Ground, built sometime between 1908 and 1929.

Eastern Daily Press: The former bottle kiln at Deal Ground in Trowse.The former bottle kiln at Deal Ground in Trowse. (Image: Archant)

It was used to dry freshly sawn green timber to meet J & J Colman Ltd's increasing demand for wooden crates and barrels.

Caroline Skinner, listing team leader at Historic England, said: "I'm delighted that we've had the opportunity to explore and assess these remarkable heritage sites in east Norwich and to ensure the protection of this area's very special industrial heritage.

"Thanks to the foresight of Norwich City Council, who involved Historic England in the early stages of the East Norwich Strategic Regeneration Area, these fascinating buildings can continue to tell an important story of a local industry that became a globally recognised brand, and the societal changes that took place in the town at this time."

Eastern Daily Press: Mike Stonard, Norwich City Council cabinet member for sustainable development.Mike Stonard, Norwich City Council cabinet member for sustainable development. (Image: Archant)

Mike Stonard, Norwich City Council's cabinet member for inclusive and sustainable growth, said: "This review by Historic England has shown just how important this area of the city is to Norwich's rich heritage.

"It allows us to understand which buildings on these sites are of national importance and which are not - something that will ensure the emerging masterplan fully respects the heritage of the area."

Eastern Daily Press: The former Colman's site off Bracondale is due to be regenerated.The former Colman's site off Bracondale is due to be regenerated. (Image: Archant)

What does the future hold for the Colman's sites?

A major plan is being developed to build 3,500 homes and create 6,000 jobs in the area around the former Colman's factory.

That includes the former Colman's Carrow Works site, Carrow House, the Deal Ground - between Whitlingham and Trowse - and the Utilities site, where a power station once stood on the north side of the river.

The locations are in various different ownerships and the idea is the East Norwich Masterplan - through a public-private initiative - will help bring together development.

The scheme is also earmarked to include a new marina and could also lead to the replacement of the Trowse Swing Bridge - which may speed up trains between Norwich and London.

The possibility of re-opening the disused Trowse Railway Station has also been mooted as part of the proposals.