Around one million Royal Bank of Scotland (RBS) account holders will soon be prevented from using cash machines belonging to rival banks.
Basic bank account holders - those without overdrafts or cheque books - will only be able to withdraw cash from RBS, NatWest, Tesco and Morrison ATMs.
The bank says that letting these customers use rival machines is unsustainable because it cannot recover the costs incurred each time a transaction takes place.
RBS - which is following in the footsteps of Lloyds TSB - also stresses that around 20,000 locations are still available to those hit by the move.
However, Marie Burton, financial inclusion expert at Consumer Focus says: "This is a kick in the teeth for many of RBS's most vulnerable customers. We would call on RBS to re-consider this move which will exclude its basic bank account holders from using the majority of the UK's free cash machine network."