Two separate major investigations in the Republic and Northern Ireland led to cross-Border swoops on what is believed to be the largest fuel-smuggling and money-laundering enterprise in the Border area.
Thirty-one locations were raided in the Armagh and south Down area yesterday. There were three separate raids in Louth and Monaghan.
The joint exercise, "Operation Spendthrift", which took months of planning, was spurred by the huge impact that petrol and diesel smuggling from the Republic is having on the Northern Ireland market. The operation in the North involved over 300 police and customs officers backed by the British army.
Investigations have been underway for a year in the North and close co-ordination with the Garda began around three months ago. The scale of the operation reflects the extent of fuel smuggling, thought to be worth more than £200 million sterling a year. The smuggling has had a major impact on the North's petrol retail industry.
Earlier this year the Financial Times reported that fuel imports to the North from the rest of the sterling area have dropped from 940,000 tonnes in 1994 to 440,000 tonnes last year. The smuggling is driven by the differential in duty: a litre of unleaded petrol in the Republic can be as much as 25 pence (Irish) less than in Northern Ireland. Diesel is similarly cheaper.
No final figure for the value of the smuggling operation has been established but one source said it generated and laundered revenue into tens of millions.
Asst Chief Const Stephen White, who is responsible for the PSNI's Southern Division, described the operation as a success, saying his officers had raided all the targeted premises, which included fuel stores, commercial premises and accountants' offices.
"I am delighted with what appears to be a very successful operation completed in partnership with HM Customs and Excise, police officers from both PSNI and the Garda and soldiers from the British army. This was a partnership approach to what has become the constant problem of fuel smuggling, tax evasion and money laundering."
Police and customs officers have been monitoring large amounts of petrol and diesel moving across the Border for several months. A Co Armagh businessman with interests in fuel depots on both sides of the Border was arrested in Keady and is one of the 10 people detained.
There were no arrests in the Republic but the Criminal Assets Bureau raided an accountant's office in Dundalk and removed a large number of documents.
The Money Laundering Unit of the Garda Bureau of Fraud Investigation, and Customs, raided a bureau de change outside Monaghan town and a fuel business near Castleblayney.
Customs officers seized two oil tankers, one containing 25,000 litres of petrol, in Castleblayney.
The operation was welcomed yesterday by Ms Jane Kennedy, Security Minister and Chair of the Organised Crime Task Force set up in October last year to tackle organised crime in the North.
"The government attaches high priority to tackling excise fraud and any related organised crime which robs the UK Exchequer of funds for public services and undermines honest businessmen and women. I am delighted to see Customs and the Police Service of Northern Ireland working together so effectively, with their counterparts in the South, to tackle excise fraud. As chair of the Organised Crime Task Force, I welcome all joint working which has impact on serious fraud and organised crime in Northern Ireland.
"The multi-agency approach, promoted by the Organised Crime Task Force, has produced tremendous successes this year. Today's operation is exactly the type of multi-agency operation which the task force wishes to see."
Last month, the Northern Ireland Assembly said up to £200 million in revenue was being lost by the UK Exchequer because of paramilitary gangs smuggling fuel.
The Northern Economy Minister, Sir Reg Empey, said the illicit trade was forcing legitimate petrol retailers in Border areas out of business. "It had reduced petrol imports into Northern Ireland by 55 per cent over the last few years and vehicle numbers have increased by 22 per cent."