As many as 50,000 beverages are to be given away by over 2,500 participating pubs as part of National Pub Fortnight.
The event taking place between 20 July and 5 August will see consumers who have signed up online eligible for a free beverage at participating pubs.
Vouchers will not guarantee a free drink with each pub having 25 free drinks to give away, meaning the offer will run on a first come, first served basis. National Pub Fortnight organisers have refused to name the participating pubs until the event begins, however it confirmed the majority of London would be covered.
The event aims to celebrate pubs and their place in British communities whilst also driving custom to them.
Drinks on offer include pints of Amstel, Kronenbourg and Strongbow, along with bottles of cider and.