Employers will find out late next month whether electrical workers are likely to strike over pay.
Union officials from the Amicus section of Unite are visiting sites throughout Britain over the next three weeks to test the mood for industrial action and will report their findings at a recall meeting on 20 September.
Tom Hardacre, head of construction at Unite/Amicus, told shop stewards last Thursday that the union was unable to conduct a ballot over strike action, as legally required, because the database of members was so out of date the vote would be invalid.
Instead, the union asked officials to visit its members on sites to assess whether they wish to strike.
The union has taken this action in the wake of the impasse that it reached with the Electrical Contractors Association (ECA) over the Joint Industry Board wage agreement.
Hardacre negotiated a deal but it was rejected by stewards last month and the ECA has not improved its offer.
Hardacre was unavailable for comment as Building went to press.