13 of the worst supermarket substitution fails - revealed

Would anyone be happy to receive a pregnancy test when they'd ordered condoms? Have you ever tried lining a bin with tinfoil, or made a fresh fruit salad with peach-scented shampoo?

These are just some of the more interesting substitutions that online supermarkets have offered their customers, as revealed by our research into the best and worst supermarkets.

Vegetarians seem to get a particularly raw deal: lots of customers told us about their Quorn mince being replaced by beef mince, and veggie sausages being substituted with pork ones.

And spare a thought for any shoppers watching their weight - one had a salad cruelly replaced with a bar of Dairy Milk.

Worst supermarket fails

Here's our list of the weirdest substitutions, as told to us by the shoppers who received them:

1. 'I received a sack of onions when I had ordered a bottle of white wine.'

2. 'I got extra strong mints in place of beef mince.'

3. 'I once ordered a pack of condoms for my husband and we received a pregnancy-testing kit - presumably for myself!'

4. 'Dog food was put in instead of clothes hangers.'

5. 'I got sent a bar of Dairy Milk instead of a premium salad.'

6. 'I ordered mayo and had it subbed for window cleaner.'

7. 'I received nappies instead of toilet paper.'

8. 'Baby food was replaced with tampons.'

9. 'I was given a bottle of Chardonnay when I wanted some apple juice.'

10. 'I ordered gluten-free bread and got dog food.'

11. 'Tissues substituted for sausages.'

12. 'They sent tinfoil instead of bin liners.'

13. 'I asked for a punnet of peaches and they substituted it for peach shampoo.'

Best and worst supermarkets for substitutions

Asda is the worst supermarket for substitutions:nearly half of the Asda customers we surveyed received a substitution in their online shopping in the space of six months. But that doesn't let the other supermarkets off the hook.

Amazon Fresh, with 37% of customers receiving substitutions, came in second from bottom, while Waitrose Deliver (33%) and Tesco Online (30%) came in third and fourth for grocery swaps.

Our analysis shows that online supermarkets that don't make many substitutions, or stick to sensible ones, generally tend to get a better customer score in our surveys.

This may go some way to explain why Iceland, the supermarket with the least substitutions, was voted the best online supermarket.

Sample size in brackets. Online survey of 7,004 members of the UK general public, Nov-Dec 2016. Based on previous six months.

Which? magazine editor Richard Headland said: 'Those supermarkets offering an online order service should respect their customers and get their orders right first time.

'If a substitution is necessary, supermarkets must make sure the alternative that lands on their doorstep is as close to the original product as possible to save disappointment.