The London-based architect has been kicked off the £13.5 million project in favour of a design-and-build contract that is 'extremely unlikely' to use the firm.
The practice - which won the project through an invited competition in 2003 - is understood to be furious at the decision and has been warning the client, the Vale
Patel Taylor, working with Techniker's Matthew Wells, won detailed planning permission for the project in 2003 and has been closely involved with fund-raising.
If it does go ahead in its current form, which seems unlikely, the project will involve the creation of a new 2.1 km walkway linking Penarth and Cardiff Bay, located just along the coast from the Welsh capital.
The design involves possibly the longest example of a draped structural steel beam in Britain. This stainless-steel balustrade would be supported by concrete piers designed to blend in with the cliffs.
It is understood that Patel Taylor - described by one source as 'pig-sick' - has long feared that the local authority would go down the design-and-build road.
It is believed that the council's decision was taken under the advice of its project manager, EC Harris.
But Paul Gay, from Vale of Glamorgan council, claimed Patel Taylor's original contract only took them up to the planning stage and that a design-and-build process
was being used because of the project's 'short timescale'.
Both Patel Taylor and Techniker are now bidding with a contractor to stay on
the scheme, but do not believe they will be appointed. And Wells, who was working as engineer on the scheme and has also been dropped, attacked the way the the project has been handled. 'They [Patel Taylor] came up with this unique design and need to work on
it until completion.
'It is part of the wider concerns about the competition process - but it would be a disaster if Patel Taylor did not finish this job,' he added. 'This scheme is so much more than
a bit of lighting and a handrail.'