By analysing your bank account, the app will determine when it's "safe to save," and you can set up daily, weekly or monthly transfers if you want a really structured regime. Alternatively, you can use one of the smarter options. Every time you spend, for example, the app can round the transaction up to the nearest pound and transfer the difference into your savings account, a few pennies at a time. You can also tell it to punish you for shopping at user-defined "guilty pleasures" stores, putting a small amount aside each time you treat yourself to another unnecessary item of winter clothing.

If, however, the app notices you saving too much and leaving your current account bare, it'll tell you as much. Similarly, SmartSave will let you know if you could easily be putting more away for a rainy day. HSBC is launching the app as part of the Financial Conduct Authority's regulatory sandbox initiative, which is supporting the development of new fintech services by slackening red tape to encourage live tests. This does mean that HSBC isn't rolling SmartSave out to everyone, though, and instead will start with a six-month, invite-only trial involving 2,000 customers next week.