Patricia Hewitt, the health secretary, has been asked to block the possible move by BT to replace its software supplier for electronic patient records in London as part of the NHS National programme for IT (NPfIT).

Richard Bacon, MP, a senior member of the House of Commons Public accounts committee (PAC), last night wrote to the health secretary asking her to prevent the appointment of Cerner as the new software supplier for NHS systems in London.

His letter cited E-Health Insider’s exclusive Tuesday report that BT, the London local service provider for NPfIT, is potentially planning to switch from GE to Cerner as its main software supplier. EHI reported that a report by US analysts Leerink Swann predicted a move to Cerner in London.

The Conservative backbencher and MP for South Norfolk wrote: "I understand that Connecting for Health’s Local Service Provider, British Telecom, is about to appoint Cerner as the main software sub-contractor for the London cluster, with CfH’s approval, as a replacement for GE/IDX."

Bacon told EHI: "The evidence appears to be that they are about to, or at least appear to be about to, replace a supplier with a patchy track record with another with a patchy track record."

He added: "Given the performance of Cerner so far in the South of England, it seems rather hasty to appoint the company as the main software subcontractor for the NHS IT programme in London.”

Bacon pointed out that although Fujitsu and Cerner were meant to have deployed eight instances of Cerner’s Millennium software by Easter 2006 "so far only one system has been deployed, at Nuffield Orthopaedic Centre, which has led to serious problems.”

Bacon said that before any switch of software suppliers is permitted, the DH should first see whether Cerner can deliver working systems.

To date GE/IDX has also installed just one version of its Carecast software in London under the NHS IT programme.

If BT were to change software supplier it would leave the £6.2bn NHS IT programme dependent on just two software suppliers: US-based Cerner, which is still adapting its Millennium software to the UK and iSoft, which is running late on delivering its Lorenzo software.

Bacon urged the health secretary to block any switch. "The main contractors such as British Telecom will not appoint major suppliers without the agreement of Connecting for Health, which is answerable to ministers, so this silly and rather hasty step can be prevented."

Rather than switch to another single supplier Bacon urged trusts to be given a local choice of systems: "Indeed, it would make much more sense to allow individual NHS trusts to choose for themselves the software supplier they want, so long as there are common standards”.

He told EHI that forcing a single solution on sophisticated NHS trusts had never seemed a sensible approach: "I think that being told they had to have a single solution probably did irritate a lot of people."

Richard Granger, the director general of NHS Connecting for Health the DH agency responsible for managing the NHS IT programme, is due to appear in front of the Commons PAC on June 26.