Avon Fire & Rescue Service chiefs insist axing 40 frontline firefighters by reducing the size of crews attending emergencies is "safe".

But union reps have condemned the claims and maintain the cuts are "dangerous".

It came as firefighters held a protest outside an Avon Fire Authority (AFA) meeting on Wednesday (December 13).

Councillors approved the plans by Chief Fire Officer Simon Shilton in October, which aimed to plug a £2million budget shortfall over the next three years.

They include reducing crews on fire engines attending 999 calls from five to four.

But Mr Shilton told the AFA policy & resources committee on Wednesday that the expected financial deficit had now worsened to more than £3million.

He said trial exercises had been carried out which showed response times could still be met and emergencies tackled safely with just four firefighters on an appliance.

Mr Shilton said it was the "least worst scenario" and that it meant not having to close a fire station or take fire engines off the road, both of which he said would have an impact.

But Avon Fire Brigades Union chair Matt Senior told the committee: "When fewer firefighters are riding appliances, firefighters in control rooms will have to mobilise additional vehicles on blue lights. 

"If a call comes in close to that now empty station, help is not close by.

"Stretching resources in this way will increase response times overall. This is a public safety concern."

He said a fifth firefighter on a ladder appliance played a vital safety role by communicating directly with colleagues entering a burning building.

Mr Senior said: "Removing this firefighter places officers under pressure to commit firefighters into buildings without safety monitoring.

"It is for exceptional circumstances where it is believed life would be lost by waiting for additional resources.

"It is categorically not a 'safe system of work', and we condemn any attempt to deliberately convince you that it is.

"Frontline cuts are not a viable alternative and will make Avon Fire & Rescue unfit to face its future.

"We stand by our previous words – these cuts are dangerous.

"Because they are dangerous, we will continue to act and continue to resist by all means necessary to ensure the long-term safety of Avon's firefighters and the public.

"Cuts jeopardise our ability to handle the usual, let alone the worst."

Mr Shilton told the meeting the service had to balance its books, so ignoring the deficit was not an option.

He said: "It's a very difficult choice, it's a choice we would not like to have, but it's a reality we have to face, unfortunately.

"Riding fours is not new to the sector.

"We are not carving new ground here – it is adopted in other areas of the country.

"It is the least worst scenario, as opposed to closing a fire station or taking an appliance away.

"If I was to recommend closing a fire station or taking an appliance away, that will have an impact on our attendance times and that will increase the average response times for a second appliance by the pure fact we have fewer vehicles and fewer fire stations.

"The progress report requested by members demonstrates that response times and service provision can still be met."

The report to the committee said trial exercises held at Hicks Gate fire station training ground compared attendance times of having a crew of five on the first appliance to respond to a house fire, with a crew of four, to see if there were critical delays or safety implications in the crucial early moments of a blaze.

It said: "The results showed that there was less than 75 seconds difference in Breathing Apparatus entering a building, in fact in one of the scenarios the crews were faster to enter the building with both appliances riding with four fighters.

"The data supports that the riding of four Fire Service personnel on all appliances can be achieved with safe systems of work within Avon Fire & Rescue Service.

"A resourcing model of four on every appliance will not have a negative impact on the service response standards.

"A resourcing model of four on each appliance will allow the maximum number of fire appliances to be available and provide for fluctuating levels of demand and risk whilst ensuring safe systems of work are maintained."

The 40 job cuts will be made through retirements rather than redundancies.