Surely not a £10000 money transfer for 20 months though. I think he meant BALANCE transfer not BANK transfer.
No, he did mean it.
One example:
https://www.mbna.co.uk/credit-cards/mbna-credit-card/
Money Transfers
Transfer funds from your credit card account to your current account – enjoy 0% interest for 20 monthsfootnote 1 on money transfers made within the first 60 days of your account opening (4% handling fee applies).