Ambulance staff could take industrial action in a dispute over changes to their working conditions.

The Great Western Ambulance Service (GWAS) says it needs to change the shift system to handle increased demand from 999 calls.

It said the changes might even benefit frontline staff by not having to attend calls near the end of shifts which can now mean they have to go home late.

But Unison claims that the changes are not fair on staff.

Simon Newell, regional organiser for Unison, said: “We are seeking views from members on a range of issues.

“The accident and emergency redesign programme significant changes to our members working arrangements and shift patterns and meal break provision as well.

“Many shifts are 12 hours long and currently staff can take two breaks but the employer is proposing to reduce that to a single break of three quarters of an hour in what can be a 14-hour shift.”

He added: “It seems the trust is bent on pushing through the changes and is trying to bully and intimidate staff into agreeing to changes they are reluctant or, in some cases, cannot comply with.”

Some staff are said to face a 500 per cent increase in childcare costs if they worked the new shifts.

But GWAS spokesman John Oliver said the changes were being made to ensure the right numbers of vehicles and staff were on duty at peak times.

He said the service was recruiting 81 new frontline staff, including paramedics, as well as making changes to shift patterns and rotas.

“The changes are designed to be beneficial for patients and also help crews as well,” he said.

Mr Oliver added that a consultation process started five months ago and accepted that the changes were unsettling to some staff.

Some changes had already been made and some will take effect in the next few days.

But he said the Great Western Ambulance Society would continue to speak to staff to try and resolve any issues.