Robbers made off in a stolen car after an attempted break-in at a Santander bank branch in Lytham tonight.
The glass door of the bank in Clifton Street was smashed in the raid and police have cordoned off the building.
The Lancashire police force incident manager said: "Three males attacked the Santander branch just before 6pm.
"They managed to get away with a cash box. The cash box was discarded and police have recovered it.
"Their car was recovered in a street further away.
"They made off in a stolen car and at this stage we haven't been able to find them."
An eye witness, who arrived at the scene at about 6.30pm, said: "I arrived a couple of minutes later but from what I understand there were some security guards coming to change the cash at Santander and some guys jumped them.
"They did get away with one big box of money but they dumped it. There was a police officer walking up the street with it.
"The security guards had locked themselves in the bank.
"There were a few people standing about on the streets giving statements and about three or four policeman."
The branch has been targeted by criminals before.
In 2016, it was one of five north west Santander branches to shut down its cash machine due to "potential criminal activity and vandalism".
And in 2013, robbers armed with axes took £85,000 in cash in a terrifying attack. The gang was traced and jailed for a total of 27 years in 2015.