Field & Trek operates 11 stores, mainly in the Southeast of England, and specialises in outdoor and camping clothing and equipment from brands such as The North Face, Berghaus and Merrell. It also sells products via its web site.
Sports Direct has an option to buy the remaining 40 per cent of the business for an additional£5 million within the next five years. The acquisition signals deputy chief executive Mike Ashley's ambition to enter the outdoor sector.
In the year ending January 12, 2007, Field & Trek generated sales of£14 million.
Sports Direct chief executive Dave Forsey said: 'This strategic investment by the company helps to fulfil our objective of expanding our outdoor leisure offering. We will continue to seek to create value for the company's shareholders via such acquisitions and investments.'
Sports Direct also has nearly a 30 per cent stake in specialist outdoor chain Blacks Leisure, but under Takeover Panel rules, Ashley is precluded from launching a full takeover bid for the retailer until the end of August.