"Let's say it in a diplomatic way - it's a nonsense. Running Eurostar with such a track in the UK is a nightmare both in terms of punctuality and reliability," said Guillaume Pepy, the general manger of French railways company SNCF.

Railtrack, the company which owns and maintains the British rail network, announced it may not complete phase two of the channel tunnel link due to heavy debts - a move described as "absolutely incredible" by Mr Pepy.

SNCF launched the final stage of its high-speed Mediterranean link on Wednesday, which on completion in June will allow passengers to travel from Paris to Marseilles in three hours.

Public funding

The French managers said that the high level of public financing of the railways made the 25 billion franc ($3.7bn) link from Valence to Marseilles possible.

Britain's railways are now privately owned, and have been beset by problems following a train crash late last year, which began a major overhaul of the network, causing delays and chaos.

"We are shocked when we see the economic debate in the UK about the condition of the track.

"This couldn't happen at any level in France. We just do the work and then settle the financial side later," said Mr Pepy.