The BCS said it could not yet consider the motion because the 50 signatures obtained so far have been sent as an e-mailed list of names. It says that the signatures on the motion have to be in written form.
It is possible that some members who have given their signatures by e-mail may not convert their signatures to paper. If backers present fewer than 50 signatures, the institute will not proceed with the EGM.
A spokesman told Computer Weekly that the BCS had taken legal advice, and concluded that under its bylaws, that signatures in support of an emergency general meeting had to be supplied in handwritten form, rather than as a list of names.
"Signatories means 'physically signed' by unless otherwise defined," it said in a statement to Computer Weekly. "At this point we have received an e-mail requisition for an extraordinary general meeting; we have not received 50 signatures."
"BCS has absolutely not rejected a request for an EGM motion. We were expecting to receive a letter with physical signatures attached as required by our bylaws," it said.
Supporters of the motion raised concerns about the way the BCS is conducting its £5m transformation programme, a lack of communication with its 70,000 members, and an alleged lack of financial transparency. The motion calls for a vote of no confidence in the board of trustees and the chief executive and for a pause in spending on the BCS transformation programme.
Its supporters include IT lawyer and former BCS president, Rachel Burnett, Elisabeth Somogyi, a former BCS trustee, Rajan Anketell and former trustee and BCS councillor and David Tidey, head of IT at Wandsworth Council and vice-chairman of the BCS Elite group.
The BCS said that it had received an email from the motion's co-ordinator, Len Keighley, with a list of names, "some of which we have not be able to identify as members."
It said it has asked Keighley to supply the physical signatures of the people who are supporting the motion and their membership numbers to allow it verify them as voting members of the BCS. "As soon as these are received, we will immediately start the process of convening an EGM," it said.
Len Keighley, who stood down as a trustee of the BCS in February to co-ordinate the motion, said he had re-contacted the motion's supporters to ask for the signatures in electronic and written form. He said had received a postive response so far.
"I feel that the bylaws were sufficiently vague for the form of the signatures not to be completely clear, especially as all BCS elections have not required a hard signature for a number of years. I have sent a request for the signatures both in electronic and hard form so that we have all bases covered," he said.