Print ads for the clothes range invite readers to text the keyword SCHOOL to a dedicated shortcode, 65006. The keyword is followed by a number that denotes where the ad was placed, which allows M&S to track how enquiries were generated.
Respondents receive a text message linking them to the 'Back to School' mobile internet site, which was built by Incentivated, and features photos and prices for the range.
The site features a 'click to call' function that connects customers to the M&S Direct call centre.
M&S is offering discount vouchers to consumers who enter their email address into the site.
Jonathan Bass, managing director at Incentivated, said: "This mobile service allows mums and dads to browse the M&S Back to School ranges when they're out and about."
Separately, M&S will use mobile to support its customer loyalty scheme. Personalised emails will carry banner links to a web registration page where customers can sign up to receive SMS alert for product news and offers. They will receive no more than three alerts over any two-month period."