Aedas has won planning for the ￡22.5 million redevelopment of a historic office building in Birmingham after altering its original design.

Councillors rejected the architect’s first scheme which was described by one as a “modernist monstrosity” and likened to a “UFO landing on the rooftop”.

But it won approval after cutting the amount of glass used in the design, an act that convinced English Heritage of its merits.

The scheme, for a Victorian office on one of Birmingham’s finest commercial streets opposite the cathedral, will retain and restore the listed facade and original banking hall as well as rebuilding a 1990s extension at the back.

Labour councillor Barry Henley told the Birmingham Mail: “The design has clearly improved. It is not as good as I would have liked but it is acceptable. The way the top floors are no longer entirely glazed is a huge improvement.”

And Councillor Paula Smith, Lib Dem chair of the conservation and heritage panel, added: “We appreciate that the architects have listened.”

The development will see legal firm Wragge and Co relocate from the office to new premises at Snow Hill in 2013.

Dan Beddow, of Aedas, said: “Our plans for 55 Colmore Row take into consideration its historic nature. With this in mind the listed Victorian front will be carefully cleaned and repaired so many views of the building from Colmore Row will be unchanged.

“Reinstating the historic 1870 banking hall as a main feature on the ground floor will bring this hidden and forgotten gem back into daily use.”

The current occupant, solicitors Wragge & Co, is to vacate the building and move into new premises designed by Sidell Gibson on nearby Snow Hill. Gensler has been appointed interior architect on that project.