A new 46-storey residential tower with sky lounge is set to be built in Birmingham city centre at the gateway of the planned HS2 terminal.

Developer Nikal is revising its original vision for the second phase of the Exchange Square project in The Priory Queensway.

City council chiefs awarded planning permission last year to the project which was initially going to comprise 223 apartments, a public square and retail units across two blocks of nine and 16 storeys respectively.

Now, Manchester-based Nikal is amending the plans to create a part seven-storey, part 46-storey complex with around 565 apartments.

CGI of revised plans for phase two of Exchange Square
CGI of revised plans for phase two of Exchange Square

There would also be outdoor terraces and garden areas, retail units and a residents' sky lounge and garden on the 46th floor.

Although specific details of the final planning application are not yet available, the project is likely to be the tallest residential tower in Birmingham if built as proposed - four storeys higher than Moda Living's '2one2 Broad Street' project.

Nikal said the building work would start in spring 2018 and take three years, subject to planning approval.

Construction work is well under way on phase one of the Exchange Square project which comprises 603 apartments ranging from studios to three-bedroom units.

It will also have rooftop gardens, parking for 187 cars and 78 bikes and 27,500 sq ft of ground-floor retail space, across three buildings of nine, 16 and 27 storeys respectively.

Nick Payne, managing director of Nikal, said: "Our thinking around the revised proposals for phase two is inspired by a desire to produce a truly landmark building that will announce to those travelling by HS2 they have arrived in Britain's 'Second City'.

"With our site lying adjacent to Birmingham Curzon HS2, it's the perfect opportunity to respond with a dramatic and architecturally stunning structure which will eclipse the tall buildings already being produced in other major cities such as Manchester.

"We also want to produce a scheme that will complement the three residential towers under construction for phase one.

CGI of revised plans for phase two of Exchange Square
CGI of revised plans for phase two of Exchange Square

"The Birmingham skyline is undergoing an exciting transformation and we feel it's ready to accommodate statement structures that signpost this progress.

"We're finalising our revised proposals for phase two at the moment and hope to submit our application over the next few months."

Exchange Square is part of the wider, £350 million Masshouse regeneration project by Nikal on the site of the old traffic island of the same name.

Earlier phases include the Hive and Masshouse apartment blocks but work on another element, called Lighthouse, has stalled after initially starting in 2015.