At the height of their fame, the reggae band UB40 sold 120m records, but an increasingly bitter feud has set brother against brother in a legal dispute that has reached the high court.

The family feud – featuring rival UB40 websites – centres on who has the right to use the name UB40. In one camp is Ali Campbell, the front man who left in 2008 and recruited Mickey Virtue and co-frontman, Astro. They have named themselves UB40 featuring Ali Campbell, Astro and Mickey Virtue, and are due to play London’s O2 next month.

In the other camp are the remaining six members of the band, who say they are the only ones who can use the UB40 name and began legal action two years ago. The claimants are original members Robin Campbell, Jimmy Brown, Norman Hassan, Brian Travers and Earl Falconer and Duncan Campbell, who replaced Ali Campbell as lead singer.

Edmund Cullen QC, representing the six, said last week at the high court that they were recognised by fans as “the true continuation” of the band that produced hits such as Red Red Wine, Signing Off and One in Ten, written about the UK’s record number of unemployed at the time.

The six insist Ali Campbell’s band has no right to use the UB40 name in any form and are seeking an injunction and damages against that band, who they accuse of “passing themselves off” as UB40.

Cullen argued that the new band was seeking to exploit the “substantial goodwill” built up by the original UB40 since the split. He told the court the dispute had moved online, with both sides claiming the right to use the UB40 website.

Cullen said Ali Campbell’s band should be prevented from using the name UB40 in any form and ordered to give up the profits made from exploiting the original band’s goodwill.

The court heard that all the original band members were initially employed by their production company, DEP International Ltd, which has been in liquidation for years. Ali Campbell and his band have said they were “assigned” all of its rights in June last year, including its goodwill, the website and the trademark in the UB40 name, and that they have acted entirely within their rights.

As far as fans were concerned, UB40 without Ali Campbell and Astro was not UB40 at all, their barrister, Tom Hickman, told the court.

He claimed the case should be “struck out” as unarguable because UB40 had ceased to exist in legal terms in 2008. The new group was merely “seeking to exploit the goodwill associated with the pre-2008 band … just as Robin, Duncan and their band have sought to do.”

Ali Campbell stated in 2014 that he had not spoken to his brothers Robin and Duncan since 2008. The Birmingham band had three UK and two US No 1 singles, and still has many loyal fans.

Last week was the first time the high court heard arguments in the case. Judgment is expected next week.