A row has erupted over the methods used by managers at two HBOS branches in Scotland, aimed at motivating staff to make more sales.
Experts say HBOS should have used carrots, not cabbages
It started when a cabbage was placed on the desk of a cashier in Glasgow. Another manager in Paisley gave a worker a cauliflower.
Union chiefs, who demanded an inquiry, called it "totally unacceptable" and the bank said it had apologised.
A business expert described the tactic as "hurtful".
John Nolan, national leader of the Amicus banking union, said: "I'm totally surprised, obviously, and hopefully we can get this resolved.
"It's a totally unacceptable way of getting staff to meet targets. We have agreed procedures in place to deal with people who under-perform.
"We believe the cabbage incident was an isolated one but obviously someone has taken the initiative to actually outdo the other individual.
"It's a hot potato in relation to the position of selling and we do live in that environment unfortunately."
He added: "The company has been pretty successful over the last couple of years, so they don't need to revert to these tactics anyway. They owe their success to the staff."
Catherine Smith, an international banking strategist, said: "It's an imported idea and not a very good one and it's also improper selling - under law.
"There are various English-speaking countries around the world, including the United States, with very aggressive selling attitudes."
She added: "It is not British to humiliate people for the sake of getting more sales. It's hurtful and it's not really British to use hurt as a means of motivation.
"We tend to use the carrot rather than the stick."
A bank spokesman said: "We encourage our managers to deliver strong customer service and sales performance.
"We focus on positive measures such as good bonuses for strong performance, but we very much regret we got it wrong on this occasion and have apologised to the staff concerned.
"We have taken steps to remind all of our managers of the responsibilities they have to their colleagues."
HBOS was formed by the merger of Halifax and Bank of Scotland in 2001. The banking group employs about 70,000 staff, with 67,000 based in the UK.