CALAIS, France -- Train services between Britain and France beneath the English Channel resumed Wednesday but the disruption stoked by striking French port workers the day before persevered.

Making life more difficult for those truckers trying to get on trains were illegal migrants trying to take advantage of the snail's-pace traffic to sneak onto trucks that are heading for Britain.

Eurotunnel, which runs those shuttle trains, said traffic resumed Wednesday morning. The Eurostar passenger train service, which carries about 10 million people year across the Channel, also started running a normal schedule, though the company warned travellers to arrive extra early.

Both companies cancelled all trains Tuesday after ferry workers, striking over expected job cuts, swarmed train lines and set tires alight.

Migrants from Sudan, Eritrea and elsewhere are camped by the thousand in the port city of Calais trying to reach Britain, where they believe they will have better job prospects. Some slept overnight on a grassy slope alongside the main road to the tunnel.

Many milled among the trucks as they inched along toward the tunnel Wednesday, darting in and out of lanes.

Truck drivers expressed frustration at their inability to stop the migrants from sneaking aboard.

Migrants "are everywhere," said Lucas Soskinski, a driver for Polish company Elltrans. "But where is the police?" he added.

And Martin Degrood, a driver for Dutch company Rutom Cargo said he didn't "know what the solution is." He noted that sometimes police come and force migrants out of one truck, and "they say 'go over there.' And (the migrants) go over there -- and they take the next truck."

The growing number of migrants in Europe has prompted France to announce thousands more places in centres for asylum seekers and emergency beds in Calais, as well as a police task force to help dismantle smugglers' networks.

Britain's foreign office updated its travel advice Tuesday, warning travellers around Calais to keep car doors locked against illegal migrants trying to reach Britain.

Angela Charlton in Paris and Jill Lawless in London contributed to this report.