From 6pm tonight, we do not know if the Army will cope

Britain will become a more dangerous place from 6pm today when firefighters begin their 48-hour strike. While the country is on high alert over possible terrorist attacks, members of our fire and rescue service will be on the picket line.

The firefighters would be likely to suspend their indust-rial action in the event of a very serious incident but they would, inevitably, arrive late at the scene.

The Government readily admits that the replacement fire service, provided by military personnel crewing Green Goddess fire engines, will be considerably inferior to that normally offered by members of the Fire Brigades Union. An internal Ministry of Defence memorandum obtained by The Independent concedes that it would be "much more limited".

Even a relatively prosaic chip-pan fire could get out of hand without the availability of experienced firefighters.

Response times will be greatly reduced, partly because the antiquated Green Goddesses are restricted to a speed of 50mph. Some doubt has even been expressed over whether the 50-year-old vehicles could reach such a speed safely.

Most Green Goddess crews will not be able to enter burning buildings because they will not be equipped with breathing apparatus. They will merely hose down buildings from the outside, even if people were trapped inside, because entering would be too dangerous.

Any emergency 999 call will be connected to the usual centre. If a fire engine is required, the request will be put through to specialist support staff who will alert the nearest service personnel crew. The Green Goddess bases will not be at the fire stations.

While the soldiers, sailors and members of the RAF who have been drafted in to the auxiliary service are under instructions to give high priority to saving lives rather than to protecting property, their effectiveness will be severely limited by their lack of training. The government memo says: "The MoD would not be seeking to replicate the current firefighting capability but to minimise, as far as possible, the danger to human life."

Deaths and injuries are far more likely to occur during the firefighters' industrial action, which is due to begin with a 48-hour stoppage starting tonight, followed by three eight-day strikes planned for 22 to 30 November, 4 to 12 December and 16 to 24 December. While the auxiliary fire service will only have 12,500 military staff responding to 999 calls, the local authority fire services have almost 50,000 frontline firefighters at their command.

For the five counties of the West Midlands, for instance, there will be fewer than 50 Green Goddesses, which were all built between 1953 and 1956, compared with 211 fire engines on a normal day.

The Government's contingency plan, which is known as Operation Fresco, will be delivered by troops with five weeks' basic training compared with 14 weeks' preliminary instruction for FBU members whose effectiveness is greatly enhanced by working alongside experienced staff under the leadership of highly qualified fire officers.

During the first national fire strike in 1977, which until today had not been repeated, many of the middle to senior managers in the fire service were not members of the union and were able to help soldiers deal with emergencies.

Green Goddess fire engines were directed by experienced personnel. Some of those senior personnel – apart from chief fire officers – have since joined the FBU and will be on strike with their subordinates. Firefighting methods were also relatively basic.

Although firefighters in those days were expected to do considerably more than simply turn up to incidents promptly and squirt water at the conflagration, techniques have moved on considerably to deal with a wider range of threats today.

The government memo accepts that military personnel would have particular difficulty in dealing with chemical spills, radioactive substances and "major industrial, commercial, rail and transport fires". The paper concedes that "the MoD will provide a limited capability to deal with toxic substances".

Over the past 25 years, road accidents have made up an increasing proportion of the duties of fire crews. Hospitals are known to be deeply concerned that Green Goddess crews will not be able to use the kind of sophisticated cutting equipment to rescue people that is available to local authority firefighters.

In some areas, National Health Service trusts have established special surgical teams to deal with people who may become trapped in vehicles. In some circumstances, they may have to resort to amputation to free crash victims from wreckage.