BRIGHT dreams that at long last Britain will soon be linked to continental Europe by a tunnel under the English Channel are beginning to sour, thanks to a pileup of problems on the British side of the channel. Work on the ``Chunnel,'' which will be for rail traffic only, is going ahead more or less as planned, and there is reason to expect that, despite cost overruns, the 24-mile undersea artery being built by an Anglo-French consortium will be operational by the target date, June 1993. One end will be at Coquelles, near Calais, the other at Cheriton, near Folkestone, close to the white cliffs of Dover.
On the French side, a high-speed rail link between Paris and Sangatte will be ready, enabling travelers to ride on trains capable of speeds up to 200 miles an hour. The picture on the British side, however, is much gloomier.
British Rail announced on Nov. 3 that it is postponing by one-year plans to build a high-speed rail link connecting Folkstone with London and points north. BR explained that the cost of a link had escalated, that enough money to pay for it was not immediately available, and that more time was needed to consider fresh options.
Cecil Parkinson, British secretary for transport, admitted that the French had gotten their act together, but that his own country had not.
This means that legislation enabling work on the high-speed rail link to start has been shelved until next November. It had been scheduled to go before Parliament in a few weeks. The earliest date forecast for a completed high-speed rail link on the English side is 1998, but before that happens, there are bound to be long arguments about the route it will take.
On Nov. 5, thousands of people marched through central London, protesting the environmental disruption likely to be caused by high-speed trains traveling from the Kent coast to the British capital.
Initially, the cost of the link on the English side was put at 1.7 billion. That was before the environmentalists began making a case against the rail link about 18 months ago.
They successfully argued the need for deep cuttings to be built to prevent excessive train noise in densely populated parts of Kent. In addition, BR said a long and expensive underground tunnel would have to be built from the outskirts of London to the capital's center. The extra measures, however, would have doubled the cost of the rail link.
The Nov. 5 marches here were largely provoked by a BR decision to abandon the projected underground rail tunnel into London. Instead, new plans will be drawn up to allow for trains going to and from the channel to travel on the surface through some of the capital's most heavily built-up areas.
The British government is insisting that, like the Chunnel itself, the entire venture must be paid for by private capital, with no public subsidy at all. After the City of London signaled unwillingness to find the extra 1.8 billion needed, BR decided to postpone the high-speed connection.
By contrast, France's rail link is being boosted by injections of public money and will be ready on schedule. There is thus a virtual certainty that Chunnel travelers will be whisked at high speed across French terrain, but will travel at roughly one quarter of the speed on British soil.
Eurotunnel, the consortium building the undersea tunnel, believes the initial attractions of the Channel Tunnel may be undercut by the disparity.
Cost of the boring is proving more expensive than estimated.
Alastair Morton, joint chairman of Eurotunnel, is confident that the extra cash will be forthcoming from a consortium of about 200 banks, some of them Japanese finance houses eager to earn profits from the Chunnel.