The majority of city firefighters have reported for work - despite the current four-day strike, say Bucks and Milton Keynes Fire and Rescue Service.
BRFS claim the FBU gave “improper notification” to the fire authority of its intention to induce its members to strike.
Chief Operating Officer Jason Thelwell said: “The legal issue came about because of changes that the FBU has had to implement regarding the collection of union subscriptions from its members in Buckinghamshire and Milton Keynes, which came into effect in October.
“Although we have not received formal notification from Buckinghamshire and Milton Keynes FBU that it has called off the strike, all our stations are working almost as normal.
“We are pleased that firefighters have taken this decision and that they won’t suffer further financial losses.”
BRFS advised its FBU members to seek clarification from their union’s solicitors, and suggested that they sought guarantees that staff would not be liable to a range of sanctions, including dismissal, if they went on strike.
Mr Thelwell added: “We are still urging the public to take care during the strike period, and at all other times too, but it is almost a case of ‘business as usual’ in Buckinghamshire and Milton Keynes.
“A number of our firefighters had already made the decision to work during the strike even before the legal issue arose.
“Disappointingly, the situation has led to a great deal of abuse on social media, from people who don’t work for us and who don’t know all the facts, directed at Buckinghamshire Fire & Rescue Service’s senior officers.
“We wish they would put as much effort into encouraging the public to stay safe during the strike as they do into calling us names.
“All we had asked was for the union to confirm to its members that this strike action is 100 per cent legal. The fact that it couldn’t convince its members that it would be seems to have been problematic.”