Make the most of Barclays PC Banking with a Barclays Instant Savings Account Barclays Bank PLC. Reg. No: 1026167. Registered in England, Reg. Office: 54 Lombard Street, London EC3P 3AH. A minimum balance of £100 is needed to start earning interest on a Barclays Instant Savings Account. Full details, including interest rates, can be obtained by calling the Barclays Information Line on 0800 400 100.