The pioneering craft, designed by owner Donald Campbell, was recovered from Coniston Water in Cumbria in 2001 and rebuilt by a restoration team.
Mr Campbell was killed in an accident on 4 January 1967 whilst attempting to reach 300mph to break his own water speed record.
The Campbell family gifted Bluebird’s wreckage to the Ruskin Museum in Coniston, Cumbria, in 2006 and the museum built an extension to house the restored Bluebird.
Engineer Bill Smith led the restoration project and oversaw the Bluebird’s return to water when it raced on Loch Fad, Isle of Bute, in August last year.
It reached speeds of 150mph during trial runs.
But the Ruskin Museum has expressed “surprise” at an announcement by the Bluebird Project restoration team that it will be doing test runs on the same lake in July.
The Bluebird Project has now been issued with a legal threat by the museum.
Ruskin Museum spokesman Tracey Coward said there had been no ‘agreement or consent’ for the Bluebird to return to Bute this summer.
Ms Coward said: “We’re very focused on Bluebird returned to Coniston water and were very surprised that the decision was made to return it to Loch Fad. There’s been no agreement or consent.
“We want to work with Bill to see Bluebird return to Coniston.
“Bill’s team have done a fantastic job and Bluebird proved herself on Bute.
“We really hope we can speak with Bill.
“Bluebird’s home is Coniston and we really want to bring her home.”
Bill Smith, project manager of the Bluebird restoration, said: “The deal has always been we would build a boat, it would go in the museum and we would get it for three months of the year – otherwise it would deteriorate.”
After completing trial runs on Bute in August, Mr Smith said there was plans to return Bluebird to Coniston Water this year, but the museum weren’t ready for a homecoming so the restoration team arranged to return the craft to Bute this July to do more trials following alterations completed since last summer.
Mr Smith, 52, said: “When they weren’t ready, we said we knew where we could do some training to iron out the boat.
“After they said we could return to Coniston this year we started recruiting volunteers, called up safety divers and booked holidays and time off work.
“We also done a lot of logistical work, then in January they pulled the plug.
“We learned a lot on Bute last year and there’s other things we want to figure out.
“We said we would go to Scotland again and told them to tell us when Coniston’s ready.
“Then they said they couldn’t be bothered and wanted their boat back.
“We’ve all been waiting a long time for this, but they said they would get their lawyers. It was very childish.
“We said we’re going to Bute anyway, but do your best to get us on Coniston, they’ve not got their house in order.
“We basically got left on our own to do our part.”
Mr Smith said it was important to keep the boat operational.
He said: “We want it for three months of the year to keep it running.
“It’s like if you just leave your car in the garage, it won’t start again.”
He added: “I’ve been involved with this project for 23 years and ten or 11 of those have been renovation work. It’s a very big commitment.
“To try and have them move the goalposts at this late stage, it doesn’t sit well.
“We’ve got nothing to disagree about.
“It matters to us, the nation and the public.
“The project is bigger then me and them, we’re just looking after it for the next generation.”