Conservationists have objected to the demolition of John Madin's NatWest Tower in Colmore Row and its temporary replacement with a public square.

A new application was lodged in January to demolish the 1970s tower and build an interim public space on the site while detailed plans for a replacement were drawn up.

Conservation groups have called for the 22-storey tower to be saved on what English Heritage called "a vigorously architectural corner site" where Colmore Row joins Newhall Street.

Plans for its demolition and the temporary public space (CGI below) will be considered by the city council's planning committee on Thursday.

The Twentieth Century Society has made a final plea for the office block to be saved and re-used, saying the building is of "significant architectural interest" and could easily be adapted.

But council planners say it has been derelict for a decade with no-one prepared to take it on.

English Heritage, the city's Conservation and Heritage Panel and the Victorian Society all object to the creation of public open space on the site - even for an interim period - and have called for a replacement building to brought forward.

English Heritage, which despite its objections has granted it a Certificate of Immunity from Listing, said: "This is a vigorously architectural corner site in the conservation area and its character would be completely undermined by the demolition of the existing building and by the absence on the site of a replacement building."

CGI of planned interim public realm to be built as part of the demolition of the NatWest Tower - 115 Colmore Row is on the left
CGI of planned interim public realm to be built as part of the demolition of the NatWest Tower - 115 Colmore Row is on the left

The council's planning department says it has sought a guarantee that either construction of the replacement building would begin within 12 months of demolition or the open space would be of high quality, fitting the prominent Colmore Row conservation area.

In addition, a set of ornate aluminium bank doors (below) are to be salvaged and preserved if the tower is demolished.

The doors were created for the building, officially called 103 Colmore Row, by the late artist and sculptor Henry Haig and bear an abstract triangle pattern based on the NatWest logo.

Now developer Sterling Property Ventures, which acquired the building with Rockspring from British Land last year, has vowed to save the doors and either re-use them in a new building or hand them over to the Birmingham Museum and Art Gallery or Mr Haig's family for preservation.

The council was contacted by Mr Haig's family after the demolition plans were submitted in January.

The family said: "The original aluminium-cast banking hall doors must be removed intact, without damage and be preserved as part of Birmingham's rich artistic works heritage."

And they confirmed they would keep them in a family museum if they could not be displayed in Birmingham.

A public consultation on plans for the building which would replace the tower is launched next week.

Ornate aluminium doors at the foot of the NatWest Tower in Colmore Row
Ornate aluminium doors at the foot of the NatWest Tower in Colmore Row