Paramedics took almost double the estimated response time to reach a teenager choking on a pen top because the nearest crew was on a lunch break.
Ben Stirland, 13, from Consett in County Durham, died on 11 January after swallowing the plastic top.
It took nearly 12 minutes to reach him. There is no suggestion he would have survived had the nearer crew attended.
The North East Ambulance Service (NEAS) is involved in a union dispute over payments for staff during meal breaks.
Ben died at Newcastle General Hospital, two days after swallowing the pen top.
Under arrangements introduced nationally in June 2005, paramedics are not paid for meal breaks and, as a result, are not called out to emergencies during break times.
Unions and ambulance service managers elsewhere in the country have reached agreements to allow staff to respond during breaks, but discussions in the North East have so far ended in stalemate.
Simon Featherstone, NEAS chief executive, said: "I would firstly like to record our condolences to the family of this young boy, this was a tragic accident.
"If the Consett crew were not on a meal break and had been on duty from their station, we estimate their travelling time to this particular location as approximately six minutes.
"We understand the sentiments and frustrations expressed towards the meal break situation, although A&E staff will state that they really value the guaranteed uninterrupted period during a busy shift."
Almost 50 extra staff have been introduced since the new arrangements were put in place two years ago, he added.
A meeting to resolve the long-running dispute is planned for 30 January.
Joel Byers, of Unison, said: "I think it's ridiculous that an emergency service does not have a 24-hour cover.
"It doesn't matter how many extra staff the trust employs, there's no guarantee that they will be the closest to an incident.
"Our sympathies are with the family of this boy. Now I don't know whether it would have made a difference or not, but we should be available - the police are, and the fire service are."