Nearly half of parents admit to being "piggy bank raiders" who occasionally dip into their children's cash to cover costs such as parking, takeaways, taxis, school trips and paying the window cleaner.
Some 46% of parents of children aged between four and 16 years old said they have taken cash from their child's piggy bank stash, a survey from Nationwide Savings has found.
The average amount taken over the past 12 months was £21.41, while one in 10 (10%) parents had taken £50 or more during that period.
Mums are more likely to raid their child's piggy bank than dads - but dads are more likely to swipe bigger amounts of cash - the survey found.
The months after Christmas, when many families are getting their finances back on track, also appears to be the time when piggy bank raiders are most prolific, with many parents saying they tended to take money between January and April.
The survey of 2,000 parents found those in Yorkshire and the Humber, the North East of England and the South West of England are the most likely to raid their child's piggy bank, while those in London, Wales and the North West of England are the least likely.
Some 15% of piggy bank raiding parents used the cash to pay school lunch money, while the same proportion also use it to pay a bill.
One in nine (11%) used the money for school trips and 11% used it as loose change for parking. One in 12 (8%) took the money to tide themselves over as they were broke.
A further 12% of piggy bank raiders used the cash for other purposes - with bus fares, hair cuts, petrol costs, paying the window cleaner and also using their child's money for the "tooth fairy" being among these expenses.
And one in 20 (5%) parents who used their child's cash spent it on a takeaway.
The vast majority of parents (93%) said they put the money back afterwards - and only around two in five (39%) of children noticed the money had disappeared.
Nearly one third of parents who took money said they had confessed to their child, while 23% sneaked the money back into their child's piggy bank. A further one in seven (14%) added "interest" onto the amount they had borrowed, putting more money in than they had taken out.
Andrew Baddeley-Chappell, Nationwide Building Society's head of savings and mortgage policy, said: "Despite being in charge of instilling a good approach to finance, almost half of parents have been caught in spring raids on their kid's piggy bank stash. While liberating change for parking or to pay school lunch money could be viewed as excusable, one in 10 parents actually borrowed more than £50 in the last year, including for paying bills.
"Although more than half of kids don't even notice the money has gone, it is reassuring that the vast majority of parents, including me, pay the cash back, with one in seven paying back even more than they borrowed to ease their guilt. Based on these findings, perhaps there are even more reasons for parents to encourage their kids to start the savings habit."
Here are the main reasons for piggy bank raiding parents taking the cash, according to the research for Nationwide Savings:
- To pay school lunch money, 15%
- To pay a bill, 15%
- School trips, 11%
- Parking, 11%
- Other (reasons included paying the bus fare, a milkman, taxis, a cleaner, hair cuts, a window cleaner, petrol and the tooth fairy), 12%
- I was broke, 8%
- Takeaways, 5%