Police have been outside a bank in Bamber Bridge throughout Monday (15 October) morning.
South Ribble Police say they are investigating an attempted fraud.
The branch in Station Road had three police vehicles parked up outside around 11am.
Police confirmed a 37-year-old man of no fixed abode has been arrested on suspicion of fraud and is currently in custody.
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The RBS branch is one of those targeted for closure by the bank.
A closure date of 29 January 2019 has been set with RBS saying only around 100 customers-per-week are visiting the branch.
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