The private contractor that runs Kent’s non-emergency ambulance service says it is taking steps to improve its performance after health chiefs flagged up a string of missed targets.

G4S has been under scrutiny for some time after a period which saw the operator fending off complaints about its service, notably from patients missing appointments.

A report has now revealed the service is still falling short of key targets and G4S has not always had either enough drivers or vehicles to meet demand.

On a key measure to ensure patients arrive for a scheduled appointment on or within the time slot, G4S has hit the target on 71% of journeys - way short of the contract threshold of 95%.

G4S says many patients are not ready when they are collected and pick up times change on the day.

A target that patients booked to be taken home within 60 minutes of being discharged shows that barely half are - with just 47% of journeys complying against a target of 95%.

However, G4S has raised questions with health chiefs about the terms of the contract.

It has argued the specifications do not reflect the reality of the type of patients they are dealing with and the longer journeys needed.

A report to be presented to a cross-party health scrutiny committee on the performance of G4S states: "Due to the increased pressure from the variance from plan, G4S has found it challenging to improve performance to meet their contractual key performance indicators."

In a statement, G4S Patient Transport Services Managing Director, Russell Hobbs said it was in negotiations with health bosses over the terms of the contract.

He said: "While we recognise there is more work to be done to improve the service we provide, the current KPIs [key performance indicators] were set when we took over the contract and do not reflect the service performed now.

"This is because there has been an increase in long journeys, single passenger journeys, and an additional requirement for ambulances for patients with much more complex requirements.”

The statement added: “A Care Quality Commission (CQC) report published in December reflects the progress that we have made in our patient transport services and found our staff to be respectful, compassionate and caring.”

Complaints over the past six months represented just 0.2% of the 162,857 journeys made, he added.

G4S runs two contracts: one taking patients from both Kent and Medway to acute hospitals excluding Darent Valley Hospital and a second transporting patients for renal dialysis.

The firm provides free, non-emergency transport for people who are unable to get to and from hospitals in Medway and Kent any other way.

It took over the £90m contract in 2016, when troubled previous operators NSL opted not to seek a contract renewal.

In a statement, the West Kent CCG (Clinical Commissioning Group), which is leading the negotiations with G4S, said a fuller report and presentation would be considered at a meeting in April.