The Government today ordered a major review of the structure of the railways to prevent "further suffering" to passengers.

Announcing the shake up, Transport Secretary Alistair Darling said the way rail was privatised had led to ''fragmentation, excessive complication and dysfunctionality''.

The time had come to streamline rail organisations because ''passengers and taxpayers will only suffer further if this fragmentation is not addressed,'' said Mr Darling.

One organisation that will definitely remain is Network Rail, the Labour-created Railtrack replacement which, Mr Darling said, was ''already operating in the public interest''.

He also firmly ruled out a return to nationalisation of the railways, stressing that he was a believer in the partnership of the private and public sectors. Before today's announcement there was speculation that the review would lead to a removal of the Health and Safety Executive's (HSE) rail safety role and also a possible diminishing of the power of the Strategic Rail Authority (SRA).

There was also speculation that the SRA's chairman Richard Bowker could lose his job.

Mr Darling today confirmed that the review would look at the HSE's rail safety role but praised the work of Mr Bowker, with whom he said he enjoyed ''an extremely good relationship''.

Mr Darling also appeared to rule out a suggestion that eight regional ''fat controllers'' would be appointed with responsibility for both tracks and trains - a link which was broken by privatisation.