The pub, owned by licensee Tom Gee, beat 16 other category winners to the top award at the BT Sport Great British Pub Awards, organised by the Publican's Morning Advertiser (PMA).
In addition the pub won the title of Best Freehouse 2013. Judges were impressed the all-round success story of the Red Lion and felt Gee was a licensee with a clear vision and a firm grip on the direction of the business.
Publican’s Morning Advertiser editor Rob Willock said: "Being named the BT Sport Great British Pub of the Year 2013 is a tremendous achievement , and the Red Lion is thoroughly deserving of this accolade.
"The Red Lion is a pub business that proves it is possible to innovate and introduce fresh ideas while still retaining the atmosphere of a quintessential English inn offering something for everyone."
Licensee Tom Gee said: "It was amazing to be named Best Freehouse Pub 2013, but to win the overall award is mind blowing. I am so happy that the Red Lion Inn has won this prestigious award, especially as we beat so many other excellent pubs across the UK for the title.
"My congratulations and thanks go to all of the staff at the pub and the award is really for them. It is great recognition for all of their hard work.
"The two awards will take pride of place in the pub and I know that our customers will be pleased for everyone who works at The Red Lion Inn."
Interactive map: The winners
The pub has an £800,000 plus annual turnover, an extensive beer offer including beers from its own four-barrel microbrewery, five boutique letting rooms and a strong food offer led by chef Chris White - who has worked with Heston Blumenthal.
The pub has driven wet sales alongside food and accommodation, achieving a combined increased in turnover of 23% in the past year.
The awards were presented by Inbetweeners and Cuckoo star Greg Davis at a Wild West-themed awards dinner at London's Park Lane Hilton.
The 2013 national winners are:
Best Charitable Pub - The Longhorn, Walsall, West Midlands
Best Smoking Area - Cheers Café, Bar and Tavern, Fraserburg, Aberdeenshire
Best Cellar - Farmers Arms Inn, Combe Florey, Somerset
Best Family Pub - South Causey Inn, Stanley, County Durham
Best Food Pub –Treby Arms, Sparkwell, Devon
Best Sports Pub – Bar Sport, Cannock, Staffordshire
Best Entertainment Pub – The Grafton, Kentish Town, London
Best Spirits Pub –Rummer Hotel, Bristol
Best Wine Pub – Harris Arms, Portgate, Devon
Best Bar Team – Broadfield Ale House, Sheffield, South Yorkshire
Best Cask Beer Pub – Dove Street Inn, Ipswich, Suffolk
Best Managed Pub – St James Taven, Piccadilly Circus, London
Best Freehouse – Red Lion Inn, Cricklade, Wiltshire
Best Partnership Pub – So! Bar and Eats, Harrogate, North Yorkshire
Best Community Pub – Maypole Inn, Taunton, Somerset
Best Newcomer – Anchor Inn, Wingham, Kent
Best Turnaround Pub – George Payne, Hove, East Sussex