A small number of outbreaks of foot-and-mouth disease in Northern Ireland would have overwhelmed veterinary services, former agriculture minister Brid Rodgers warned in 2001.
Ms Rodgers said a spread of the virus would have required the large-scale secondment of public sector workers to help with containment measures, as well as support from the RUC and British Army.
In a memo to her Executive colleagues, she also advised that it would be impossible to seal the border on the island of Ireland to prevent the illegal movement of animals.
The outbreak of the highly contagious foot-and-mouth led to the culling of millions of animals and the banning of the export of meat from the UK.
The virus was detected at an Essex abattoir in February 2001 and spread rapidly, including a small number of cases in Northern Ireland and the Republic of Ireland.
Farmers went into self-isolation to prevent disease spread and a number of sporting and community events were cancelled.
Newly-released files from the Public Record Office in Belfast reveal the preparations going on at Stormont to control and limit the spread of the disease.
When Ms Rodgers sent her March 26 memo there had been two confirmed outbreaks in the north and one across the border in Co Louth.
The minister said tenders had been sought for mechanical vehicle washers to be installed at the ports of Larne, Warrenpoint, Stranraer and Cairnryan.
She said vehicles “are being monitored on cross-border roads in South Armagh, and the RUC are continuing to undertake roving patrols in a wider area”.
Ms Rodgers said she did not believe Northern Ireland faced an increased risk of further spread provided farmers “behave sensibly and responsibly”.
Turning to the border, Ms Rodgers said there was an “obvious comparison” to be made between efforts to combat the virus across the island of Ireland.
She said: “On the major roads our garden sprayers targeted at northern-bound traffic are clearly much less impressive than the power washers and other sophisticated spraying machines in operation for southern-bound traffic.
“There is no doubt that the travelling public expect a serious attempt to clean vehicles entering Northern Ireland, and will continue to make a comparison between the two administrations.”
The minister said the measures to monitor the movement of animals across the border had the “potential to cause considerable embarrassment”.
She said: “For presentational reasons, there would be an advantage in maintaining an official presence at all 175 recognised border crossing points.
“We estimate that to maintain a presence on all 175 would require around 2,000 people.
“Even if we monitored only the most important ones on a 24-hour basis - and there are perhaps 35 of these - we would still require of the order of 600 people.
“This would have huge implications for the provision of other public services throughout Northern Ireland.”
She said freeing up Civil Service staff to help would affect other services such as maintaining essential water supplies and winter gritting on the roads.
Ms Rodgers added: “I have to say that in such an extension of our activity on the border will not be effective, simply because fixed checkpoints can be easily bypassed over fields or through forests if someone really wants to move animals or other goods illegally.
“We have already acknowledged that it is impossible to seal the border, and the only real advantage of this course of action is presentational.”
She said she believed it was better to target resources in areas where there had been outbreaks of the virus.
Turning to contingency planning, the minister warned that a spread of the disease in Northern Ireland would create “enormous problems”.
She said: “Each fresh outbreak will immediately need 70 to 100 people to contain the outbreak and begin slaughter at a rate of around 300 sheep or 100 cattle a day. This excludes veterinary staff.
“To double this rate will require an additional 20 people a day. We would also face a serious shortage of specialists, particularly vets, even with the assistance of private veterinary -practitioners, and of slaughtermen.
“We estimate it would only take three or four concurrent outbreaks to overwhelm us, depending on the location and the number of animals in the affected area.
“We would almost certainly need to second administrative staff not only from other government departments, but also from the health and personal social services and from education boards, from district councils and from other parts of the public service.”
She added: “We should have to seek considerable logistical and other support services from the RUC and the army.”