A pregnant cashier pressed a panic button to foil an armed raid on a bank, a court heard.
Darren Katumba, 21, had already robbed another bank of £2,000 when he attempted a similar raid on Santander in High Street, Gillingham.
He approached the cashier and handed her a note demanding £1,000 in £50s - and telling her in capital letters: "Don't ---- about."
But she pushed a panic button and a security shutter came down. Katumba fled empty-handed and headed for the railway station.
He was caught on bank security cameras and was arrested soon afterwards at Bromley South station.
Maidstone Crown Court was told the bank worker was left distressed and an ambulance was called to check her condition.
Katumba admitted attempted robbery and robbing the Co-operative Bank in Dartford and has now been jailed for six years.
Prosecutor Keith Yardy told the court Katumba went into the Co-operative Bank in Hythe Street, Dartford, on June 27 and handed a note to a cashier.
In it he demanded £1,000 in £50 notes and £1,000 in £20 notes and warned: "No funny business."
The bank worker did not challenge him because of company policy. He put the money in an envelope and handed it over.
On August 16, Katumba disguised his appearance and attempted a repeat performance at Gillingham Santander.
Judge Charles Macdonald QC said the planning was quite striking as the 21-year-old, of Millard Road, Deptford, south east London, researched all types of robbery and decided not to arm himself in the hope of escaping a more severe sentence if arrested.
He also targeted banks that were close to railway stations for his getaway and not near to police stations.
Judge Macdonald said of the Gillingham raid: "It may be you didn't realise she was pregnant, but that's the sort of risk you take when you raid banks.
"It is a sad feature you have utterly let down your family. The motivation seems simply to have been greed."
Daniel Fallon, defending, said Katumba was extremely shocked when he discovered he had tried to rob a pregnant cashier.
When arrested, he confessed to committing the Dartford robbery - otherwise, he would not have been caught.
"It is his first time in custody," said Mr Fallon. "He comes from a good family and has a very decent background."