Freight services through the Channel tunnel have also been badly disrupted, embarrassing the rail industry, which promoted the tunnel as a reliable and faster alternative to ferries.
With an escalating strike threatening to cost businesses millions of pounds in lost production, companies are reviewing their commitment to rail transport.
British Steel, the third-largest user of rail services after Powergen and National Power, said some foundries were bringing in more raw materials by road.
'They will have to shift more on to the roads as the strike continues,' said Mike Hitchcock, a spokesman for British Steel, which spends pounds 70m a year on rail transport. 'A prolonged strike could affect our long-term strategic decisions about rail use.'
Redland Aggregates, one of Britain's biggest quarrying companies, which moves 10,000 ton of stone daily, said it had no option but to use more lorries.
ARC, another quarrying company, estimated that each day of the strike cost it pounds 500,000 in overtime and rescheduling. ARC's David Weekes said the company had invested pounds 30m to transfer stock throughout southern England.
'You can switch to road if the destination is within easy reach of the quarry, but you cannot send lorries the other side of the country. It costs too much,' he said.
MAT Transauto, a bulk car carrier, which uses the railways to deliver 5,000 cars a week has moved up to 20 per cent of its vehicles by road during the strikes.
Trade organisations for the transport industry said there was evidence that small companies were switching from rail to road, but added that many companies were tied into rail contracts. But the strike would make renewal of those contracts harder.
The action came at a time when the rail industry was hoping for a resurgence in business after freight services through the Channel tunnel started last month. The Freight Transport Association said confidence in rail was still fragile.
Railfreight Distribution, a BR division which spent pounds 800m to launch Channel tunnel rail services, admitted that the strike was not a good advertisement for the tunnel. Railfreight, which pays fees to Eurotunnel, normally runs about 60 trains through the tunnel each week.
The Rover car group was one of many companies which had switched from ferries to the tunnel.
Combined Transport Ltd, which also uses the Channel tunnel, has switched some traffic back to ferries. The knock-on effect of the strike has meant CTL's average of 18 Channel tunnel services each week has been halved.
More coaches are also on the road as companies help staff get to work. Shell UK, which employs about 1,700 people in London, ran 20 coaches at a daily cost of up to pounds 500 a coach.
The Post Office which, like several companies, could seek compensation from British Rail for the disruption, has put an additional 350 vans on the roads to handle 13 million items of mail normally carried by rail on each strike day. It is also using 21 extra planes.Reuse content