A BBC News investigation into the highest-category callouts has found rural areas waited over 50% longer.
That equates to four minutes - something that can make the difference between life and death for those in cardiac arrest, stab victims and patients struggling to breathe. So what can and is being done?
Every part of the health service would readily accept more money.
About £2bn a year is spent on answering more than 10 million urgent calls - although only about 5% of these are classed as "immediately life-threatening".
That sum equates to just over 1.5% of the health budget.
More money could certainly help deploy extra paramedics and vehicles, to ensure better coverage in rural areas.
But even those working in the service acknowledge there is a limit - crews sitting around for long periods with nothing to do is clearly not the best use of NHS resources.
One of the most important steps in rural areas is training up members of the community to help answer these high-priority calls.
These are known as "community first responders" and volunteer to be on call to help critically injured patients if paramedics are not going to be on the scene quickly.
Some police and fire crews have also been trained to lend a hand.
While thousands of these volunteers have been trained, the ambulance service says it can always do with more.
No matter where a patient is when a life-threatening situation develops, the simple fact remains in all probability a member of the public will be on the scene more quickly than a trained response.
And they can play a critical role. Take cardiac arrests, for example. A bystander can provide cardiopulmonary resuscitation (CPR) to patients. Even those who have not been trained can be talked through the process by control-room staff and told where to access community defibrillators to deliver electric shocks to restart the heart.
The way ambulance crews answer calls in England, Scotland and Wales has changed in recent years.
All have introduced a system that prioritises a smaller number of calls for the quickest response.
Today, just one in 20 calls is treated as the highest-priority, whereas traditionally about a third of calls were.
This is allowing crews to make faster responses to the most-in need patients, according to Adam Brimelow, of NHS Providers.
But does this help rural areas? The BBC News investigation looked at response times from January to October last year - after these changes were brought in.
It was not possible to look at a historical trend over time.
Academic research carried out during the piloting phased of the new system in England suggested it might reduce variation.
But the NHS in England believes it will. A spokesman for the service said there was now a "strong incentive to tackle the longer waits historically seen for those who live in rural and remote areas".
→ The BBC - How to reduce rural ambulance waits
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