A strike ballot against BT has been cancelled following legal concerns about the vote.
The Communication Workers Union (CWU) was forced to cancel its ballot of BT staff after it received legal advice stating there were "technical breaches" that could potentially invalidate the ballot result.
The ballot was sparked following a dispute over pay. BT had offered its staff a 2% award for this year, but the CWU has demanded a 5% pay rise.
The union said it has agreed to meet BT for further negotiations, but has pledged to re-ballot members should the talks prove unsuccessful.
Andy Kerr, deputy general secretary at CWU, said: "We're bitterly disappointed this ballot has had to be cancelled. It's devastating for our members and for trade union rights in the UK, and of course it doesn't help to resolve the outstanding issues over pay that we have with BT.
"We will take all necessary steps to allow us to re-ballot our members as soon as is practically possible. In the meantime, we will also be taking up an offer from BT for a meeting to see if there is a way to resolve this dispute without the need for industrial action."
Kerr added the cancellation of the ballot reinforced fears that union laws were outdated. He said: "The legal technicalities on which this ballot has been cancelled again raise questions over the right to strike and the extremely restrictive trade union laws that exist in the UK. The law, in our view, appears to be outdated when it comes to the provision of information."
A spokesman for BT said: "BT is pleased the CWU has withdrawn its ballot for industrial action. There were procedural issues regarding the ballot that we raised from the start and the union has now accepted this to be the case. Our door remains fully open to the union, and so we hope we can sit down and resolve this matter."