Medical support staff with as little as six weeks' training responded to more than 18,000 emergency 999 calls last year instead of qualified paramedics.

New figures highlight the dramatic rise in the number of emergency calls attended by only emergency care assistants (ECA).

According to the East of England Ambulance Trust (EEAST) data, 18,815 emergency calls were attended solely by ECAs last year – a rise on the 767 recorded in 2011.

ECAs are being used as 'first responders' and put in charge of ambulances called to a range of potentially life-threatening situations where they have, in cases, been required to resuscitate patients.

ECAs are trained in emergency first aid, deliver a range of clinical care under supervision, use ambulance equipment, are trained in emergency driving and assist with restocking and cleaning the vehicles and equipment after use.

Gary Applin, UNISON branch secretary at EEAST, said the union warned ECAs should not be used as a frontline resource as they did not have enough training to deliver a 'sufficient range of emergency clinical care'.

EEAST employs 445 ECAs who attended 24,232 emergency calls between 2011 and 2013.

Junior health minister Dr Dan Poulter, MP for North Ipswich and Central Suffolk, said it was time for EEAST to 'get a grip'.

He added: 'We need to see the senior management invest in the right numbers of staff on the front line and the right vehicles to deliver the service patients in Suffolk deserve.'

Rob Ashford, EEAST's director of service delivery, said the trust was no longer recruiting ECAs – a move which has been welcomed by UNISON.

Mr Ashford added: 'We recognise that we need more paramedics, which is one of the reasons why we have stopped recruiting ECAs and will only be taking on graduate and student paramedics, as this will undoubtedly improve the care we give to patients.

'Our current ECAs remain a vital part of the workforce but over the coming months we will be looking to train as many of them as possible as emergency medical technicians and hopefully, thereafter, paramedics.

'Developing our workforce is the right thing to do for staff and patients.'