Developers are poised to transform a second building at Manningham Mills into apartments and penthouses.

Urban Splash wants to press ahead with the next stage of the mill complex's redevelopment after the success of its conversion of the former silk warehouse, which it has called Lister Mill.

The company is in talks with Bradford Council and English Heritage about the submission of a new planning application.

It is understood early designs include apartments on the roof, but Urban Splash and Bradford Council have stressed no planning application had yet been submitted.

They added there has been no dispute about the early design suggestions and ideas were changing constantly.

The famous mill complex, once home to the Lister's textile dynasty, will eventually be redeveloped into a total of 600 homes, combined with leisure and business facilities, over the next ten years.

Simon Gawthorpe, managing director of Urban Splash Yorkshire, said: "Pre-application discussions are taking place with the planners and English Heritage on the design for the second phase of the development in the second mill. The development is key to the regeneration of Bradford."

The second mill, which stands on the opposite side of the court yard from the former silk warehouse, is expected to be converted into 150 apartments.

Mr Gawthorpe said the company was proposing similar models to the apartments in the silk warehouse but with even higher specifications.

When Urban Splash sold the first apartments in November 2004, each buyer was limited to a single property to encourage owner occupiers rather than investors.

More than 500 people waited in a line to buy the first apartments which came on the market and Mr Gawthorpe said there were now only six or seven for sale.

He said Unran Splash hoped to get planning permission and start work as soon as possible on the second phase.

The Reverend George Moffatt, team leader of Manningham parish, said he was delighted Urban Splash was moving on to the next phase.

"I am pleased with the continuing development of the mill.

"It is a continuation of a good news story for the whole of the Manningham area. The fact Urban Splash is going ahead sends out tremendous signals about Manningham."

One of the Council's senior planning officers, Chris Eaton, said: "We are in discussion with Urban Splash but we haven't seen the final designs. We have seen several images but things change. It may involve some accommodation on the roof."

A spokesman for English Heritage said: "There are pre-application discussions between Urban Splash and English Heritage regarding the second phase of the works."