HanWay Films is selling the project worldwide and handled the Lionsgate deal for MARV.
Michael Caine has come on board to play the title role, opposite Emily Mortimer.
Gary Young wrote the screenplay and Daniel Barber will direct, making his feature directorial debut after Oscar-nominated short The Tonto Woman.
The film will shoot on location in the UK starting in November.
In bleak contemporary England, an elderly ex-serviceman and widower whose best friend is murdered forcing him to seek his own personal justice.
Thykier and Vaughn produce with Keith Bell. Control veteran Martin Ruhe will serve as director of photography.
Producer Kris Thykier said: 'Harry Brown is a modern urban western that reflects the stark realities of youth crime in the 21st century both in the UK and internationally. I am delighted that Lionsgate has come on board as our UK distributor, and equally thrilled that Michael has agreed to play Harry Brown. The role is an exciting and contemporary take on the iconic characters like Harry Palmer and Jack Carter that originally brought him to fame.'
Lionsgate UK CEO Zygi Kamasa said: 'Harry Brown is a unique British thriller that is set in a genuinely terrifying world of inner city violence. We are really excited to be working with Michael Caine and the filmmakers on what we believe will be a hugely commercial release next year and continues our remit to support mainstream British films.'
Michael Caine added: 'It's a great script, a great role and a wonderful new director, Daniel Barber.'
Michael Caine and Emily Mortimer are represented by Toni Howard at ICM and Duncan Heath and Kate Buckley at Independent Talent Group.