A new agreement replaces a 2015 deal and extends the contract out to 2024.
It covers the two existing hydrogen refuelling stations (HRS), located at Shell service stations – one at Cobham on the M25 and one at Beaconsfield on the M40 – as well as four new locations.
The company expects to open new HRS at Gatwick and Derby later this year, and, two additional London-based HRS are also planned.
"We are delighted to announce our continued collaboration with Shell,” said Graham Cooley, ITM chief executive.
“We have been working together since 2015 and have developed a trusted partnership that forms a solid basis to expand in the UK and worldwide.”
Mike Copson, of Shell Hydrogen, added: “The successes we have achieved at Shell Cobham and Shell Beaconsfield are a strong step toward making Hydrogen a convenient and viable fuel choice, and we look forward to continuing to expand the UK's developing network."
ITM noted that the UK hydrogen refuelling station network has been jointly funded by the UK's Office for Low Emission Vehicles and the Fuel Cells and Hydrogen Joint Undertaking.