A full planning application has been submitted to West Northamptonshire Council Planning Authority.
The development would provide year-round training facilities, and will also be available for community use.
“I’m pleased to confirm that our detailed planning application for a new indoor training facility has been submitted,” said Saints CEO Mark Darbon.
“We are very proud of our home at Franklin’s Gardens, but we must continue to invest in our facilities to underpin our ambition to be successful at the very top of our sport and attract some of the best players in the world.
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"The vast majority of clubs across the Premiership, as well as in other elite leagues globally, already have access to indoor structures of this nature.
“The development of this facility will not only ensure that our squad can train effectively, on site, in all weather conditions, it will enable us to engage with the community in new ways, and help us attract new events to Franklin’s Gardens and the town of Northampton.
“So far, our discussions with the council have been very positive and we hopeful our application will be fully supported.”
An announcement on the outcome of the application will be made in due course.