Here's what John Lewis say:
http://www.johnlewis.com/Help/Help.aspx?helpid=9
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We do not price match any online or catalogue competitor prices. This is because we are unable to verify the availability and comparability of the goods and the standards of service and support that are offered by others. However, you can always be assured of the same dedication to competitive pricing and exceptional value you find in our department stores. For information on our shops' ‘Never Knowingly Undersold' statement, please contact your local branch."