Troubled U.K. National Health Service (NHS) software supplier iSoft has signalled that its £140 million ($276 million) sale to Australian software company IBA is back on the cards, following "constructive" talks with lead contractor CSC.

The iSoft sale had been blocked by CSC, the lead contractor in three out of five regions for the NHS's £12.4 billion National Programme for IT (NPfIT), because it firm felt the deal would not support successful delivery of iSoft's Lorenzo care records system - a core part of NPfIT.

CSC's move prompted iSoft to launch legal action against it, but this was put on ice when the two companies began talks about commercial arrangements to give CSC greater management control of Lorenzo's development.

But in a new "scheme of arrangement" issued by iSoft to its shareholders, the software firm indicated that it was moving forward with the sale following positive indications from CSC.

The discussions begun on June 6 "continue to be constructive", it said. "As a result, the iSoft directors believe that there is a reasonable likelihood that CSC will consent to the change of control of iSoft and that the [IBA] offer continues to represent the best route forward."