After wrangling over payment for a road for five years, its answer was simple: send a gift box of rock crystals and toadstools, get its workers to dress up as Bugs Bunny and Mr Blobby, and send missives containing the words of Nelson Mandela.
So bizarre is the behaviour of Birse, which has put many of its workers into therapy and last year apologised for its aggressive culture, that the victim of its recent attentions has complained to the Government and accused the contractor of harassment.
After five years of dispute over a payment of pounds 11.5m for the road, Birse Construction resorted to aseries of unorthodox methods in an effort to kick-start negotiations with its client, Caerphilly council.
Through the post, addressed to council chief executive Malgwyn Davies, came a gift box containing a rock with a fairy, candle and toadstool. Mr Davies then received a fax from Birse containing quotations from a speech made by Nelson Mandela on the day of his release from prison. The gift box, said Birse, would help Mr Davies meditate in order to keep calm. The words of Mandela would help free him from being institutionalised.
Birse also sent a video explaining how it felt to every Caerphilly councillor and dispatched six employees to a council meeting dressed as cartoon characters, including Bugs Bunny and Mr Blobby.
Last year, in something of a Damascene conversion, Birse announced a change in management technique and chairman Peter Birse acknowledged how beastly the firm had been.
Birse's group finance director, Martin Budden, said he felt the introduction of "The Birse Way", a three-year makeover involving a "boutique consultancy" and therapy sessions for the company's 1,200 employees, had encouraged the approach to the dispute with Caerphilly council.
"The whole process at Birse has been about looking to remove barriers of communication between staff and between management and subordinates," he said.
"This has freed up individuals and allowed them to say what they think without causing upset. This sort of atmosphere fosters creative thinking. The type of thing we're doing now comes from that."
Unfortunately, Caerphilly council has pointedly failed to see the joke and has complained to the Welsh Office, the Department of Environment, Transport and the Regions, and the Local Government Association that Birse's actions amount to harassment.
Mr Davies said he had been bombarded with fax messages "he does not understand the relevance of". He declined to comment further, saying: "They might think they are getting to me and it might encourage them to do more of it."
The disputes centres on the pounds 30m Rhymney Valley relief road which opened in 1993. The council which contracted Birse, Mid-Glamorgan, has been replaced by a series of unitary authorities. The question of how much is owed by the new Caerphilly council has been further complicated by the apparent withdrawal of a pounds 4m European Union grant for the project.
"We were getting nowhere with the formal channels. Every initiative we tried for talks was knocked back," said Mr Budden. "This road was built five years ago and we felt the council was playing for time."
The faxes quoting Mandela, Mr Budden explained, were intended to give Mr Davies a sense of perspective. "It was meant to help him detach himself from his institutionalised position."
The idea for the fairy gift box came from Birse culture manager Steve French, who made the device himself and admits to finding the fairy a useful meditation tool.
"We thought the dispute might be getting a bit too much for Mr Davies so we thought he could do with some meditation," said Mr Budden.