The average price of a roast is £8.24 in the Midlands, following by Edinburgh at £8.27, Bristol £8.58, Plymouth £8.78 and Stoke at £8.84.
In contrast, London is the most expensive place with an average roast price of £11.53, in second place was Liverpool at £10.91, followed by Newcastle and Sheffield both at £10.74 and Leeds £10.58.
The research from savings site VoucherCodes.co.uk also found diners were paying 125% more for the dish at different branches of the same pub company.
The study looked at the cost of a Sunday roast in almost 70 pubs within major chains, including Harvester, JD Wetherspoon (JDW) and Greene King.
It analysed the number of city centre venues and found a 40% difference between the London average and Birmingham’s average price.
Greene King has the largest price difference across the sites looked at as the cheapest meat roasts served at Hunters Moon in Birmingham and Wackum Inn, Bristol (both £5.99) were 125% cheaper than the Silver Cross in Whitehall, central London, which charges £13.49 – a difference of £7.50.
However, JDW had the most consistent pricing with a difference of just 85p between its cheapest locations (found in 14 cities costing £8.75) and the most expensive in the Liberty Bounds near the Tower of London at £9.60. JDW was also the only group offering a drink with the roast, providing additional value for money.
VoucherCodes.co.uk lifestyle editor Anita Naik said: “With Christmas just around the corner, it is certainly the season for festive Sunday roasts at the local pub.
“However, it is alarming to see consumers could be paying more than double the price for their roast, simply depending on where they live.
“With gifts to buy and, for many of us, a lot of socialising, December can be a costly month so it is worth exploring options in the local area before heading out to eat to ensure a good deal.
“The fact prices can vary so much within towns, let along across the country, shows it really does pay to do a bit of research beforehand.
“Customers should make the most of discount codes that can shave valuable cash off the bill – lots of pub chains run promotions throughout the year, which can make a difference to the wallet.”