► Arsonists set fire to cables alongside high speed lines, blocking signalling data
► Police and soldiers are patrolling stations in Paris just hours before Olympics launch
► Thousands of people delayed as trains are diverted to classic lines or cancelled

Updated 11.53
Updated 12.43
Updated 15.00

Three arson attacks have disrupted high speed train services in France, a few hours before the Olympics opening ceremony in Paris. Trains from London have been affected, along with other international and domestic high speed services within France. Prime Minister Gabriel Attal says the effect on the country’s railways has been ‘massive and serious’.

SNCF said vital cables had been damaged by the fires, and police with Olympics duties are reported to have been diverted to some major stations in Paris to help deal with crowds of frustrated travellers. Some soldiers have also been seen on stations.

11.53 update: It appears that the arsonists set fire to bundled fibre-optic cables in conduits running along the cess, knocking out signalling data circuits. SNCF president Jean-Pierre Farandou is quoted by news agency AFP as saying: ‘There's a huge number of bundled cables. We have to repair them one by one. It's a manual operation requiring hundreds of workers.’ Repairs are not expected to be complete before Monday.

12.43 update: Paris public prosecutor Laure Beccuau said an investigation had been launched into ‘deliberate damage of property likely to harm the fundamental interests of the nation’.

15.00 update: Limited services have been restored between Paris, Brittany, Bordeaux and Toulouse, after emergency repairs. Some trains are also running again between Paris and Lille, but SNCF is warning that delays and disruption are expected to continue until Sunday or Monday.

Eurostar has been affected because one of the attacks damaged LGV Nord near Arras, between Paris and Lille. Some Eurostar services between London and Paris have been cancelled, while those trains which do run are being diverted on to the slower classic line between Lille and Paris, and Eurostar has warned that journeys will take about 90 minutes longer as a result, with some cancellations likely to continue until Monday. It said its staff had been ‘fully mobilised in stations, in the call centres, and on board to assist and ensure our passengers are fully informed’.

LGVs Atlantique and Est have also been damaged by the attacks, and SNCF is asking its passengers not to try to travel on these lines. SNCF said there had been a ‘massive attack aimed at paralysing the network’.

Another attack, this time on LGV Sud-Est to Lyon, was prevented early on Friday morning by railway maintenance staff carrying out routine duties on the site at Vergigny, south east of Paris.

There is no obvious connection with the Olympics so far, and no-one has admitted responsibility, but the disruption has come on one of the busiest days of the year for French Railways. The system was braced to deal with many thousands of people arriving in Paris for the start of the Olympics, while a second surge of passengers consists of people leaving Paris at the start of the summer holidays.