However, the trade-off between the costs and benefits of size is affected by another factor: trade restrictions.

ECONOMIST: How big should a nation-state be?

Another factor is a sense of defeatism in Chernobyl-affected people, many of whom had to leave homes their families had lived in for generations.

CNN: 26 years on: helping Chernobyl's children

One factor that may have weighed on the bank's mind is that every one of the affected customers could have taken their complaint to the Financial Ombudsman Service (FOS).

BBC: Santander U-turn on free business accounts