Repairs to a damaged pipe examined by foot-and-mouth outbreak investigators may not have been carried out because funds were not available, it was reported today.
Official reports into the recent Surrey outbreak are being published today and are expected to say faulty drainage pipes at a nearby laboratory could have released the disease.
According to media reports this week, the investigation found a damaged pipe at the Pirbright site contained the virus, which could have spread to nearby farms by workmen after being brought to the surface by flood water.
The studies are also expected to say workers renovating the laboratories may have spread foot-and-mouth on their car tyres.
Today Defra will publish the two reports - the findings of an investigation by the Health and Safety Executive into the outbreak of the disease on two farms near Guildford and a biosecurity review led by Professor Brian Spratt, of Imperial College, London.
The Pirbright site is shared by the Government-funded Institute for Animal Health (IAH), an international diagnostic laboratory, and pharmaceutical company Merial Animal Health.
The BBC said it had learned that investigators had identified at least five breaches of bio-security at the IAH.
It reported that leaks in the pipe linking Merial to a treatment plant run by the institute are among the breaches, as well as with problems with drains failing to cope with floodwater and failures in monitoring and controlling people and vehicles.
Photographs of the pipe were said to show signs of damage from tree roots and some misaligned joints.
Investigators were reported to have found records indicating that for several years there had been concerns about the state of the pipe, but that no repairs were carried out, possibly because funds were not made available.
They are not thought to have pinpointed a single point of failure allowing the virus to escape, but they have outlined a scenario for what they believe happened, according to BBC reports.
It is believed that the virus was present in the pipe, which is allowed under current rules, and then flushed out during flooding.
Vehicles used by contractors are thought to have driven into the flooded area, allowing the virus to be picked up.
They were then said to have driven to another flooded road, where the virus was washed into nearby fields and cattle became infected.
The BBC said sources said the reports did not suggest negligence at the site.
Environment Secretary Hilary Benn will also outline the Government's response to the reports on the outbreak.
HSE experts were sent to the Pirbright site, near to the two affected farms, after it was confirmed the strain of foot-and-mouth disease found in infected cattle was the same as one used in the labs there.
An urgent review, led by Professor Brian Spratt, was launched into biosecurity arrangements at Pirbright.
In its interim report published last month, the HSE said there was a "strong probability" the outbreak originated from the IAH or Merial sites.
The HSE said "release by human movement" had to be considered as a real possibility and a number of "biosecurity issues" had arisen in relation to the site's effluent treatment system.
These issues included the integrity of the system and all associated pipework, the potential for the virus to have entered this system during the specified time period and whether heavy rain and flooding could have overwhelmed the system.
After it emerged the final reports would raise the possibility of a breach in biosecurity at Pirbright, there were calls for compensation for farmers who were affected by the outbreak.
The first outbreak of the disease, in a herd of cattle kept by farmer Roger Pride in fields at Normandy, near Guildford, was discovered at the beginning of August. A neighbouring herd, owned by John Gunner, tested positive days later.
Defra is due to lift the remaining national animal movement restrictions tomorrow, along with the surveillance zone in Surrey, in the latest step back towards disease-free status for the country.