The first sites will open later this year at London’s Liverpool Street and Paddington station.
John Vincent, co-founder and CEO of Leon, said: “When we started we imagined what fast food would be like in heaven – fast, fresh and naturally flavourful.
“And just like traditional fast food, we aim to be where people need and want us – on busy high streets, in airports and in train stations. This partnership with SSP in UK train stations means that together we can bring naturally fast food to even more busy people across the UK."
SSP, the operator of food and beverage outlets in travel locations, has also announced its interim results for the six months ended March 31st 2016.
The company reports an operating profit of £30.9 million, up 28% at constant currency (22.6% at actual exchange rates) and like for like sales are up 3.3%, driven by growth in air passenger travel and retailing initiatives.
Revenue is up 5.9% at constant currency (4.4% at actual exchange rates) to £897 million.
Kate Swann, CEO of SSP Group, said: “SSP has made further good progress in the first half of 2016 and we continue to deliver our strategic initiatives.
“Constant currency operating profit was up 28% driven by good like-for-like sales growth in our existing business, new contract openings, which are building our presence across the world, and further operational improvements.
“I am particularly encouraged by the pace of development in our North America and Asia Pacific operations.
“Looking forward, the second half has started in line with our expectations. Whilst a degree of uncertainty always exists around passenger numbers in the short term, we are well placed to benefit from the structural growth opportunities in our markets and to create further shareholder value.”