Haulage firms have been put in an "impossible" position, a Birmingham boss has said, after it emerged fines dished out to drivers found carrying illegal immigrants had tripled.

One city company said it had stopped going through Calais altogether because its drivers were facing "inhuman" conditions, caused by Operation Stack.

Phil Benton, of Bentons Haulage, said the firm had been forced to put a block on using the port for deliveries during the height of the problems there.

Mr Benton, 54, whose company runs 79 lorries and is based in Tamworth Road, said health and safety regulations meant drivers were not even allowed to check their vehicles properly.

He said: "They are giving out fines of £2,000 to drivers who aren't even, under UK law, allowed to actually check their loads.

"We can't ask our drivers to climb up to check if immigrants are lying on the roof because that infringes HSE laws.

"If they had a checking zone with raised platforms that would be possible but they haven't got one. It must be down to the authorities to do the checking, using sniffer dogs, CO2 checking equipment and so on.

"I can't go up there or ask one of our drivers to go up there because I could fall off and break my neck. We need to get the army in to check all the lorries as they come over."

Under Home Office rules, drivers can face an on-the-spot fine of up to £2,000 for every person found hidden on their vehicle at any UK port and the Eurotunnel.

Home Office figures released under the Freedom of Information Act show the number of fines has risen from 998 in 2012/13 to 3,319 in 2014/15.

It comes as the UK and French governments face pressure to end the migrant crisis which has seen numbers swell in Calais over the summer.

Thousands of migrants have attempted to get to the Eurotunnel and nine have been killed since June.

An estimated 5,000 migrants displaced from countries including Syria, Libya and Eritrea are now believed to be camped in and around the port.

Operation Stack has seen lorries bound for Dover "stacked" on a closed section of the M20 while other traffic is diverted onto surrounding roads.

This has seen drivers left without food, drink and other facilities for extended periods.

Mr Benton said: "We have had drivers stuck for 30 hours - it's not nice, huge queues of lorries and the drivers are just expected to sit there and wait.

"It's disgusting and we certainly can't ask our drivers to put up with it."

Mr Benton said he had driven to the port to catch a ferry at the weekend - through areas which had been left burnt out by striking workers who had set fire to piles of tyres in a dispute with bosses.

He explained: "It's an immense problem, both from them and the immigrants and it's showing no signs of going away.

"Billions of pounds have been lost from companies carrying perishable goods and we have been seriously delayed in making some of our deliveries. It is putting the haulage industry under even more pressure."

Donald Armour, from the Freight Transport Association, said the vast majority of drivers took steps to properly secure their vehicles.

But he said this was becoming increasingly difficult in the face of immigrants' determined attempts to smuggle themselves on board coupled with long queues on the other side of the Channel providing more opportunities to do so.

Mr Armour added: "Whereas they used to come in ones or twos, you're now often finding ten to 20 people smuggling themselves on board at any one time.

"The public ask why drivers don't secure their vehicles better but many go to great lengths to stop this happening.

"You find immigrants getting in through the roof, slashing the canvas sides of lorries or jimmying off locks. When you're facing that kind of determination, there is only so much you can do and the only real solution is better control of the immigration situation."

A Home Office spokesman said the increase in fines is largely the result of the growing numbers of migrants at Calais since 2012 rather than a more punitive approach.

He said only seven per cent of those caught were British drivers but too many lorries had insufficient security.

He said: "Most hauliers take their responsibility for vehicle security seriously but, despite co-operation from the British haulage industry, one third of lorries arriving at the UK border do not have basic standards of security.

"The purpose of civil penalties is to ensure that all drivers are taking every reasonable step to stop migrants from boarding their lorries. Drivers who have properly secured vehicles will not receive a fine."