Martin Lewis has shared his catchy “Sad Fart” trick to ensure shoppers know their consumer rights if their complaint about a faulty item they purchased is dismissed.

Appearing on This Morning on Tuesday (1 July), the Money Saving Expert founder explained his mnemonic that he said has used for 20 years.

Lewis spelt out his mnemonic device to viewers at home, explaining that items must be “satisfactory quality, as described, fit for purpose and last a reasonable amount of time”, or they will be considered faulty.

Presenters Cat Deeley and Ben Shepard asked Lewis how to measure the final letter ‘R’ for reasonable time, to which the financial journalist replied: “It’s defined by what a reasonable person says is reasonable.”