M&S paid the search engine to have its own online flower business promoted every time consumers search for Interflora.
Google users are offered a link to M&S’s florist site underneath the search result for Interflora under the sponsored link section.
As spokeswoman for Interflora confirmed the action but declined to comment further.
M&S claims that the practice of paying for keywords via Google’s AdWords service is an “industry-wide” and “not unlawful”.
The florist has previously said that the AdWords’ policy increases its advertising costs.
In a blog last year it said: “We are very serious about protecting our brand name ’Interflora’. Our brand name is also a registered trade mark and the whole idea of registering marks is to protect them from mis-use by third parties.”
Earlier this year, the European Court of Justice ruled in favour of Google after luxury brand Moét Hennessey Louis Vuitton had claimed Google’s AdWords service undermines brands and breaches European trademark law by allowing rival advertisers to purchase trademarked keywords.