Nearly 40 years of radio history will be wiped off the dial with the rebrand of Birmingham's BRMB to Free Radio. Owner Orion Media, run by former Chrysalis Radio boss Phil Riley, announced the rebrand of the Birmingham broadcaster along with three of its sister stations in the Midlands – Mercia, Beacon and Wyvern. Riley said the content of the stations, which currently share about 75% of their programming outside of breakfast and drivetime, would remain unchanged. Orion is the latest commercial radio group to relaunch stations under a single brand, beginning with the rollout of Global Radio's Heart followed by sister network Capital and Smooth Radio, which is owned by GMG Radio, part of the group that publishes MediaGuardian. Riley, the chief executive of Orion Media, said: "The decision to change the name of our stations after each one has been broadcasting in their areas under their original names for so long has not been easy or one that we have taken lightly. "We have given this a great deal of consideration and undertaken detailed research. The original on air names of each station means a lot to all of us at Orion, and we know and understand the deep affection many people have for those names. However, the radio market has changed dramatically recently and we have to adapt and respond." BRMB was the UK's fourth commercial radio station when it launched in 1974. It was followed by Beacon in 1976, Mercia in 1980 and Wyvern two years later. Riley said the "Free Radio" name was chosen because it was "easy to remember, easy to spell, and is flexible enough to work in a number of different ways. It's not free as in cheap, it's free as in freedom to have a bit more character". The four stations have a reach of 889,000 listeners between them, according to the latest official Rajar figures, with BRMB the biggest with an average weekly reach of 359,000. Riley said the new name would make the stations a better to sell to advertisers. He said no content would be changed – or jobs lost – as a result of the rebrand. He added: "Although the names are changing, the commitment we have to provide the best mix of music and presenters along with local news, sport, weather and traffic remains our No 1 priority. "Even when we are in network mode on Free Radio, we will be broadcasting from and ensuring the station serves only the needs of the region." Orion Media also owns Gem 106 in the east Midlands and the Gold AM station in the west Midlands, which will not be rebranding. guardian .