The internal strife now threatening to tear the UBP apart is not the first in the party's 44-year history.

Infighting, personality clashes, political differences and racial tensions have rocked the party before, not least in the late 1970s when a group of black MPs began pressing for change from within.

The Black Caucus, as they became known, issued a list of demands to their party in 1976 which included a call for it to elect more black MPs to the House of Assembly.

Barbara Harries Hunter, in her book The People of Bermuda: Beyond the Crossroads, wrote: "They felt that the United Bermuda Party was no longer as responsive to black aspirations as it had been and that progress in integration had slowed."

She quoted a report they sent to then-Premier Sir Edward Richards which read: "The UBP must become a truly bi-racial organisation, continuously working on and solving racial problems to ensure the wellbeing of our country, and to protect the majority from the detrimental influence of Black and White separatists."

A source close to the party told The Royal Gazette: "The black members filed a report saying the party wasn't paying attention to black needs. They were pretty much ostracised and treated as traitors for speaking out."

Sir Edward was replaced as leader by Sir John Sharpe, a Premier who was popular with the electorate, but who was eventually forced to quit after pressure from his own party members.

In February 1977, seven members of his Government, including members of the Black Caucus, resigned and accused him of bringing the party to a state of "political bankruptcy".

Six months later, he announced that he was stepping down as leader of the country. The PLP's Deputy Leader Frederick Wade said at the time that the resignation was no surprise as the UBP had "been in disarray for the last few months".

Historian Eva Hodgson said many black politicians joined the UBP with the hope of changing it from within but found that their voices were not heard once they were members.

"I know there isn't consistent racial harmony within the party," she said, adding that she was convinced former Premier Sir John Swan, a member of the Black Caucus, experienced racism in the UBP.

"I think the blacks within the party have always had to deal with what I would call racism. If you want to be kind you can say the cultural difference."

The party source, who asked not to be named, revealed that as recently as when Grant Gibbons was UBP leader, black MPs from the party held a meeting to which their white colleagues were not invited.

"That was a bone of contention because some people said it was not right. The problem is it's not an environment where we talk about this. Race is not really an issue that's honestly discussed."