An investigation has been launched after it took more than an hour to get a critically ill car crash victim to hospital.

The man, who had suffered serious injuries, was left on the roadside for half an hour before an ambulance arrived to take him to hospital more than 20 miles away.

The accident happened in Ardingly but crews were forced to take the patient to Brighton because the Princess Royal Hospital in Haywards Heath is closed to major traumas following a shake-up of emergency departments in the county.

The changes were implemented on June 19.

The injured man had to wait 28 minutes for an ambulance to arrive from Crowborough just after 10pm on Friday night.

Sussex Ambulance Service NHS Trust sets a target of reaching all emergency calls within 19 minutes, and the most serious within eight.

It took more than 15 minutes to stabilise the injured man at the scene and he then faced a further 30-minute journey to the Royal Sussex County Hospital in Brighton, where he is now believed to be in a stable condition.

One of the firefighters at the scene was forced to travel with the patient in the ambulance because there were not enough paramedics.

It has also been claimed there were four ambulances waiting outside the A&E department at Brighton. A Brighton and Sussex University Hospitals Trust spokesman denied this.

The firefighter was a member of Les Maddams' watch at Haywards Heath fire station.

Watch manager Mr Maddams said he decided to speak out because he was concerned the changes combined with the massive pressure on casualty departments could cost lives.

He said: "The man had suffered very severe injuries but we had to wait an extremely long time for an ambulance.

"There were no other ambulances available to assist even though the situation required three personnel.

"One of the firemen had to go in the ambulance with the crew and they had to travel another half an hour to Brighton.

"We talk of a 'golden hour', which is from the time of the accident to when a patient should be on the operating table. This is difficult if it takes that long to get someone to hospital.

"When the ambulance arrived the fireman was shocked to see four ambulances lined up outside the Royal Sussex Hospital. He was told this was because they were tied up with patients who hadn't been moved off the stretchers into the hospital yet. I have been in the fire service for 23 years and I have never heard of anything so deplorable."

Janine Bell from the ambulance trust said: "The crew arrived at 10.44pm, which was 28 minutes later. We recognise that this is an unacceptable delay for the patient and we will be looking into why it happened.

"We monitor all hand over times, which is the time it takes from when the crew arrive at the hospital until the time the hospital accepts care for the patient.

"It is not unusual for there to be a number of crews at the hospital at any time as the hospitals are very busy. The Royal Sussex had an extremely busy weekend and they can't always take patients from the crews straight away because of the sheer volume of patients.

"It would not have been deliberate that patients were left waiting. It is likely the four ambulances were all tied up with patients. We are experiencing a high demand as well, with about 150 extra calls a day across Sussex, well above the national average yearly increase."

Mark Purcell, spokesman for the Brighton and Sussex University Hospitals NHS Trust, said: "Friday night was a particularly busy night. We had 235 cases treated in the A&E, compared with a usual busy night which is 180 cases. The sister in charge that night refutes completely that there were any ambulances queuing with patients outside.

"She is committed to bringing patients out of the ambulances as quickly as possible even if that means they wait longer in the A&E department.

"It is one of the largest A&E departments in the South so there are often ambulances outside but certainly not queuing with patients inside.

"They might have just arrived or were dropping off patients, or maybe the crews were inside to pick up patients."

Duncan Jones, a Crawley paramedic and branch chairman of Unison, the ambulance union, said: "We have been worried about the increased workload for the other hospitals as a result of closure to trauma patients at the Princess Royal.

"If patients are being kept waiting in ambulances then that is just not acceptable.

"If a hospital doesn't take responsibility for a patient it means the crews aren't free to go and get other patients.

"It's only been a few days since the reconfigurations and if there are already problems then it makes you think."

Nicholas Soames, Conservative MP for mid-Sussex, said: "I have the gravest reservations about this switch to Brighton.

"But we cannot pass judgement this soon, we will have to see what the situation looks like after a period of time."