Former rail regulator Tom Winsor has warned that the Office of Rail Regulation is considering reforms which would give Network Rail a new role monitoring train operators' performance.

In the foreword to Transit's Transport Law Review, Winsor said that the plan may be included in a consultation later this year or early next year, and that it would fundamentally alter the nature of the relationship between operators and Network Rail.

"In 2007-08, we may see controversial proposals which would reverse Network Rail's position as the accountable provider of network services to the train operators, and instead make it the quasi-regulator of TOC performance," Winsor said. "If such a policy is proposed, there could be the mother of all rows. ORR is there to regulate Network Rail, not outsource regulation to Network Rail."

He pointed out that it would not be the first time the ORR has seriously considered tilting the balance of power in the relationship between Network and train operators.