Police arrested two men Saturday on suspicion of conspiracy to commit robbery in connection with a heist at a cash-storage depot in southeastern England that could be Britain's biggest-ever theft of currency.

Adrian Leppard, assistant chief constable for Kent Police, gave no details and did not release the men's names.

Meanwhile, a depot manager kidnapped by the robbers said the experience had been the most harrowing of his life.

Police have estimated the pre-dawn armed robbery in the town of Tonbridge on Wednesday could have netted as much as $87 million. If confirmed, the sum would make it the biggest cash robbery in British history.

Detectives and Securitas Cash Management Ltd. said it would be days before they could give a complete estimate of how much was stolen and how much of the cash police recovered Friday in a van left at a Tonbridge hotel.

"We know it's a sizable amount," Leppard said of the van find.

The thieves dressed as police officers and stopped a Securitas manager, 51-year-old Colin Dixon, as he drove home Wednesday from the cash depot near the Channel Tunnel, police said. Another group also dressed as officers went to Dixon's home, telling his wife he had been in an accident and taking her away with the couple's 9-year-old son.

Police said the gang threatened to harm Dixon's family unless he helped them get the cash from the depot, which stores money for banks and other companies. The Dixons were freed after the robbery and were all unhurt, police said.

"We're dealing with a detailed, planned operation by professional criminals," Leppard said.

Colin Dixon said in a statement that Wednesday night was the worst in his life.

"The terror of what happened and the horror of what might have happened is with us in every waking moment," he said. "This horrific experience angers me beyond belief. ... This crime was not about money for us, it was about our survival."

Two cars believed connected to the case were found on fire Thursday night.

Leppard said forensics experts were still examining the white van left outside the Ashford International Hotel with black sacks of money still inside.

He urged anyone who might have seen the kidnappings or had any information about the abandoned vehicles to contact police.

"Someone may have seen something vital to our investigation," he said. "Please think back, for however trivial something may seem to you, it could be an important piece in the jigsaw to help us solve this crime and catch a gang of dangerous criminals."

Police said Friday they had arrested a 41-year-old woman in London on Thursday after she allegedly tried to deposit $10,500 into a bank account. She was detained on suspicion of handling stolen goods, but police said she might not be connected to the depot robbery.

A 29-year-old man and 31-year-old woman also were arrested in London on Thursday on suspicion of conspiracy to commit robbery.

All three people were released on police bail, which allows them to go free but be questioned by police at any time.