Its three depots in Waltham Cross, Oxford and Maidstone will cover the region offering plant, parts and support within their official area.
The appointment follows the dealers announcement earlier this year that is was terminating its Bomag agreement by mutual consent.
The broader Ammann range offers a complete line up of compaction products, from 60kg Rammers right up to 25,000kg vibratory rollers, and including the Rammax trench rollers.
Robert Brown, managing director of Ammann Equipment, said “Leach Lewis Plant is renowned as one of the industry’s leading compact plant dealers.
“The opportunity to continue our leadership in the compaction market can only be reinforced by working together with such a professional organisation.”
Peter Whittall, Leach Lewis Plant’s managing director, said: “Our decision to partner with Ammann Equipment is a major step forward for our business, and more importantly our customers.
“The Ammann range of plates, rammers and rollers is acknowledged as a market leader in the compaction field and we are delighted that we can now offer their products and support them with our unrivalled service network.”