At a stormy meeting with John MacGregor, Secretary of State for Transport, last week, Sir Bob is said to have expressed regret at the incident and promised that it would not be repeated. However, BR said that no such assurance had been given by its chairman.
The row is the latest in a series between Sir Bob Mr MacGregor since he openly opposed the Government's proposals for rail privatisation last year.
The dispute arose after Brian Wilson, a Labour frontbench transport spokesman, requested information about the new BR timetable. Sir Bob's reply, used in a press release compiled by Mr Wilson, revealed a cut in services because of a 23 per cent reduction in government subsidy.
BR argued that the information had been openly discussed with local authorities and Transport Users' Consultative Committees and was, therefore, in the public domain. However, ministers were furious that Mr Wilson was given the information before it went to the department.
A BR spokesman said: 'The chairman cannot give assurances about how he deals with correspondence from MPs. He treats it on its merits.'