Metro drivers in Paris on Friday went on strike to protest an epidemic of crack addicts on the underground with the problem so bad that some refuse to stop at certain stations due to security fears.

Drivers held crisis talks with management and police as almost half on line 12 of the Paris underground network downed tools to raise awareness over the blight that one warned was turning parts of the French capital’s metro system into “junkie land”.

The issue first came to nationwide attention when SOS Usagers, a metro passengers’ group, and the UNSA RATP metro staff union issued a joint message on the blight last week.

They said that while the metro had been “invaded for years by groups of dealers who attract often agressive and dangerous drug addicts”, the situation had got worse since construction work had started on line 4 - one of their traditional haunts - and the addicts had amassed on line 12.

“The number of attacks on travellers and RATP staff is constantly on the rise and is reaching increasingly dramatic proportions,” they said in a joint statement. The groups have also sent messages to Paris mayor Anne Hidalgo and Gérard Collomb, the interior minister.