Liberal Democrat deputy leader Daisy Cooper has said she would be concerned whether an ambulance would turn up in enough time to save someone’s life if she needed to call 999 in an emergency.

Ms Cooper was speaking at a campaign event in Hertfordshire after party leader Sir Ed Davey said the public has lost faith in the ability of ambulance services to meet emergency callout targets.

Sir Ed described the situation as a “scandal” as the Libs Dems pledged £50 million for an emergency fund to support ambulance trusts in an effort to restore public confidence that a call to 999 will get the emergency treatments they need.

Ms Cooper said: “If it was a life-threatening situation right now, then the very first thing I would do would be to call 999.

“And I would hope that an ambulance would come, my big concern would be whether the ambulance would turn up in enough time to help save somebody’s life.”

Asked whether she had ever had to call an ambulance, Ms Cooper said: “I have. And thankfully, when I needed to use an ambulance, the ambulance was there for me because it was about 20 years ago.

“I think what we’re hearing right now is that there are many people who when they call 999, they just don’t have the confidence that an ambulance is going to arrive in time.”

The announcement, which the Lib Dems say would allow ambulance trusts to reverse closures of community ambulance stations and cancel planned closures, comes as new analysis of NHS data by the party found that 86,603 Category 2 callouts and 27,765 Category 1 callouts are estimated to miss their 18 and seven-minute targets respectively before polling day on July 4.

These categories include strokes and heart attacks, with categories listed as life and death situations.

The analysis showed London and the West Midlands would be the worst-affected regions, with more than 2,100 callouts estimated to be missed for the Category 1 target of seven minutes for life-threatening emergencies over the next 11 days.

Ms Cooper, who arrived at the event in Harpenden on the back of a green tractor, said the Lib Dems are taking the campaign seriously despite a series of eye-catching stunts.

“I think in this campaign, people will be able to see that as Liberal Democrats, we take our politics very seriously but we don’t take ourselves that seriously,” she said.

“I think we’ve managed to get the balance to show people that we are a party that cares, we have the human touch, and that we’re bringing hope and optimism to this difficult campaign.”

On Saturday, Sir Ed Davey fed chickens on a farm in East Sussex as he warned that water companies will not be allowed to “get away” with sewage dumping.

Ms Cooper said: “I think what you can see from our party leader, Ed Davey, is that he’s brought real hope and optimism to the campaign through many of his stunts, which have all been delivered with a very serious message.

“When he was on the paddleboards, he was there to talk about the sewage crisis. When he was on a water park, he was talking about our pledge to put mental health practitioners in every single school.

“And his party political broadcasts where he talks so passionately and openly about his relationship with his disabled son and his experience as a family carer, I think has really struck a chord with so many people.”