Hardline strikers blamed as rail lines sabotaged

Simultaneous acts of sabotage knocked out the signalling systems on all four high-speed railway lines from Paris, apparently in an attempt to derail peace negotiations in the week-old French transport strike.

On the high-speed line to the north, used by trains between Paris, London and Brussels, signalling cables were burnt for a length of 30 metres yesterday morning. Similar attacks damaged signal cables, or shut down signalling systems, on the TGV lines to the south, east and south-west.

Trains, including Eurostars, were still being diverted and delayed last night while the damage was repaired. Railway signalling systems are designed to fail "safe" and the danger to the public was minimal. Nonetheless, such a concerted attack on France's high-speed rail system – the largest in the world and a source of immense national pride – sent a shockwave of anger across the country.

The state-owned railway system condemned what it called a "co-ordinated act of sabotage". The Prime Minister, François Fillon, spoke of a "criminal" attack, which would be "very severely" punished.

The rail unions said that such "cowardly" attacks were "against the culture" of public safety bred into all railway workers. Some union leaders, and politicians on the far left, suggested that "forces" close to the government might be trying to discredit the transport strike which will enter its ninth day today.

It seemed more plausible that the sabotage was a desperate attempt by a fringe of die-hard strikers – or sympathisers on the hard left – to derail the first serious rounds of peace talks which began yesterday morning. With only one in five of rail workers now supporting the strike, and some grassroots meetings calling off the protest for the first time, the dispute seems likely to peter out by the weekend.

The SNCF announced that national rail services would return to something like normal today, with three out of four high-speed trains running. The Paris Metro and regional train services will, however, remain seriously disrupted.

Further strikes could be called next month if the three-way negotiations between unions, employers and government fail to resolve the dispute over President Nicolas Sarkozy's plan to scrap early retirement rights for 500,000 state sector workers. M. Sarkozy insists that he will not yield on the principle that railway, Paris transport and power workers should have a normal working life of 40 years, instead of 37.5 years.

However, the SNCF, the Paris transport system, the RATP, and the electricity and gas industries, have been authorised to offer generous packages of compensation. According to some accounts of the concessions on offer at yesterday's talks – including higher pay for older employees and pension "bonuses" – many workers would still be able to retire early on more or less full pensions. Others, who chose to work longer, would earn the right to larger pensions.

Some members of President Sarkozy's own government are said to be furious that one set of special rules for the railwaymen and others is being replaced by another. However, President Sarkozy would be able to claim that the principle of a 40-year working life had been imposed. This remains unacceptable to the more radical union leaders and to a rump of hardline transport workers.

Railway officials said that the attacks on the signalling systems of the four principal high-speed lines demonstrated substantial knowledge of how the railways worked.

On the line towards the Channel Tunnel, Lille and Brussels, a 30-metre stretch of signalling cable in an open trench beside the tracks was set on fire in the Somme department, 80 miles north of Paris. On the other main high-speed lines towards Lyons, Strasbourg and Brittany and the south-west, signalling cables were also burnt and electric signalling circuits were broken into and switched off.

Other acts of vandalism and sabotage, including blocking tracks with locomotives and jamming points with ballast, were reported earlier this week.