When Nedam, the Dutch parent group, pulled the plug on its UK division last month, it guaranteed to continue backing three PFI, in which it held an equity stake.
However, the collapse of its UK contracting arm meant that work has not occurred on these projects, leaving clients with the option of calling in Nedam's performance bond and using the money to find an alternative contractor.
It is believed that Tower Hamlets and East Lothian councils have considered this option for their schools projects. On the Tower Hamlets contract, it is estimated that this could cost Nedam £6m – which would make it cheaper for the firm to hand the job to another contractor.
A source close to the talks said: "At Tower Hamlets and East Lothian, the performance bonds look likely to be called in. Nedam has approached Botes to complete the construction work at Tower Hamlets."
Balfour Beatty is understood to have turned down a similar approach by Nedam this week.
Botes chairman Ian Botes declined to comment on the Tower Hamlets projects but confirmed that the company had put in a formal bid to take over several contracts at Ballast's southern construction division.
The sale of the PFI arm essentially collapsed last week after Bilfinger Berger pulled out of a bid for it. The UK arm of Bilfinger Berger had entered into exclusive talks with Deloitte, but its German parent said the £1-2m deal was too small to add value to the company.
This led to redundancies among senior management and more clients cancelled contracts. Unpaid subcontractors have also refused to continue to work. The services division has effectively wound down as a result, although Deloitte believes it can still sell several facilities management contracts. Costain is interested in parts of the remaining business.
A source close to Deloitte said: "There are 70 staff left. The redundancies were primarily senior management, like the team responsible for new bids."
Several subcontractors in the North-west are considering setting up a consortium to lobby Deloitte over payments that are owed.