Halfords have misled customers in a national press advert for TomTom satellite navigation systems which stated “20% off all TomTom Go”.

A complaint to the Advertising Standards Authority (ASA) challenged whether the claim "20% off all TomTom Go" was misleading, because there did not seem to be a 20% discount on the most recent selling price.

Text beneath the TomTom Go520 stated "SAVE £120 ... NOW £179.99" and alongside that text the ad showed a list of cascading prices each with a line through "WAS £299.99, £249.99, £199.99, £194.99".

Text next to the TomTom Go 720 stated "SAVE £106 ... NOW £223.99 ... WAS £329.99, £279.99, £229.99". Text next to the TomTom GO 9201 stated "SAVE £80 ... NOW £319.99 ... WAS £399.99".

Halfords said the headline would have been more accurate if it had stated "at least 20% off", because all three products shown had been discounted by at least 20% but two of the products had greater discounts.

The retailer said it had therefore undersold the offer but was still in compliance with advertising regulations.

ASA said the ad did not make clear to consumers that the discount related to the original selling price only.