The government could face legal action from schools which claim they are being bullied and browbeaten into buying a technology system which is out of date and more expensive than those they are using.
The schools are being told what to buy when they sign up for the Building Schools for the Future (BSF) programme.
Partnership for Schools (PfS), which is organising the initiative, said any school could forego the BSF cash and use its own provider.
If a school cannot afford to miss out on the funding that goes with the programme, it can put forward an alternative procurement business case (APBC). This allows it to buy its own technology provider while keeping the cash.
But the first two schools to attempt this have failed, with one of them describing the process as a "con".
Richard Gold, an education solicitor at Stone King Sewell in London, is acting on behalf of several schools fighting what they call a "one-size- fits-all" technology system.
He told The TES there could be a legal challenge. "The ICT procurement process seems to be wholly unfair, which a school could take to judicial review. Schools are asked from the outset to sign up in principle to something that is worse than their current system or forego the capital funding for the equipment. That strikes me as a non-choice."
Mr Gold added that although schools would be unlikely to go to court because of the expense, if they did it could mean severe delays for the building programme.
"The judicial review over the academy in Camden (north London) put the whole academy procurement process back, as the Department (for Children, Schools and Families) waited to see the outcome," he said.
Notre Dame High School in Sheffield, which was the first school to attempt to secure funding through APBC and fail, said its current technology system exceeded all government requirements and they would have to take a backward step if they wanted the BSF money.
Paul Haigh, assistant head, said: "The system needs reforming before it is too late and the billions of pounds' worth of investment fails to have the best impact."
The Association of School and College Leaders said the official line from PfS was that schools did not all have to have the same system, but this was exactly what was on offer.
Malcolm Trobe, the association's policy director, said: "The reality is that they are being pushed, brow-beaten and bullied into accepting a single service, which they believe is taking schools backwards on the ICT front.
"What is being said nationally is not what is happening on the ground. Whether it is the local authority that is the problem or PfS in that region, we don't know.
"It seems to be happening quite a lot. Schools are scared to raise it as an issue as they will be dealing with the local authority," he added.
A PfS spokeswoman said: "The myth that schools have no alternative but to sign up to a managed service is one we are working to dispel. There is a clear process available to schools who want to make a case to receive a proportion of BSF ICT funding. However, the school must demonstrate that its alternative will be at least as good as the managed service proposed by the local authority . and that it passes a value-for-money test.