Sarkozy sets date for his mega-canal but promises it won't touch war graves

France yesterday launched the most ambitious engineering project in Western Europe since the Channel tunnel, a scheme to link Paris to the North Sea by a canal as wide as a football pitch.

The route of the canal passes through the Cambrai battlefields of 1917 and has raised fears that it may force the removal of several British war cemeteries. French officials have, however, given written assurances to the Commonwealth War Graves Commission that First World War graves will not be threatened.

The €4.5bn (£3.9bn) project, first mooted 20 years ago, will divert up to 500,000 lorries a year from the roads of northern France. When completed in 2020, it will allow "mega-barges" of 4,000 tonnes to sail from the mouth of the Seine, via the Paris suburbs, to the Netherlands and Germany.

The Seine-Nord Europe canal will also be open to pleasure craft, allowing large seagoing motor yachts to travel from London to Paris with only a short sea crossing.

Announcing a final go-ahead for the much-delayed scheme, President Nicolas Sarkozy said yesterday during a visit to Nesle in the Somme: "The proper response of a country to the economic crisis should not be retrenchment. On the contrary, it should be investment."

The 106km-long (66 miles) and 54 metres-wide canal will connect the Rhine-Scheldt network of large waterways in the low countries and Germany with the river Seine. Starting at the end of an existing large canal at Compiègne, north of Paris, it will pass through seven large locks and cross a 1,000 metre aqueduct to reach Cambrai in northern France.

The route of the canal passes far to the east of the Somme battlefields of 1916. It will, however, cross the battlefields of 1917-18 and especially the ground of the calamitous Cambrai offensive mounted by British and Commonwealth troops and tanks in November 1917. Despite rumours among British commemorative organisations and on World War One websites, French officials say that the "preferred route" of the canal, agreed in 2008, will avoid all war graves.

Peter Francis, spokesman for the Commonwealth War Graves Commission, told The Independent yesterday that that his organisation had received "written assurances" that no cemeteries would be threatened.

The Seine-Nord canal was one of the centrepieces of a programme for the "greening" of France, agreed in 2007 by an environmental conference. Squabbles over the joint funding by the EU, France, local governments and private contractors delayed a project proposed in the 1990s.

The go-ahead given by Mr Sarkozy yesterday is part of his strategy to "spend" rather than simply cut his way out of the economic crisis. The canal, which will eventually create 45,000 jobs, is regarded as a potential economic goldmine for the struggling ex-industrial areas of northern France. For President Sarkozy, the political attractions of the scheme are bolstered by the fact that north eastern France is the political bastion of two of his likely rivals in the presidential elections next April and May: Marine Le Pen, the leader of the far right National Front, and Martine Aubry, first secretary of the Socialist Party.

When completed in 2020 it is hoped that the canal will transport 13 million tonnes of goods a year. Barges of up to 4,400 tonnes would be able to sale from Dunkirk, Antwerp or Rotterdam, to the Paris area with loads equivalent to 150 trucks or four trains.

Green politicians are divided about the usefulness of the canal. Environmentalists in the far north of France support the scheme. Local green politicians in Picardy complain that it will undermine rail freight.