A combination of winter pressures and swine flu could lead to delayed ambulances and long waits in accident and emergency, NHS chief executive David Nicholson has warned.

He told organisations to improve planning to avoid missing targets and risking added political criticism of the NHS.

My assumption must be we all need to prepare for a long winter with a lot of viral disease running on for a significant number of months

Ian Dalton

Last year the English average A&E waiting time performance between October and March missed the four hour target. That was blamed on increased demand linked to factors including bad weather and infections such as norovirus. Several ambulance trusts missed their 999 response time targets.

Mr Nicholson told the first Ambulance Service Network conference last week: “Over the last few years we have got better and better at [emergency care], though there are still significant pressures and we saw that last year. There were big problems in some areas. We can’t get complacent about the way we plan for winter.”

He warned that, because of the election, pressure to perform well would be even greater.

Mr Nicholson said: “We know pressure is going to continue this year against a completely different environment, particularly in relation to the kind of scrutiny the NHS is going to get over the next few months for obvious political reasons.”

National director for NHS flu resilience Ian Dalton warned it was possible a swine flu peak would be followed by an outbreak of seasonal flu. The NHS must also be prepared for the possible arrival of H5N1 bird flu, likely to be much more of a threat than H1N1 swine flu, he said.

Mr Dalton said: “My assumption must be we all need to prepare for a long winter with a lot of viral disease running on for a significant number of months.”

The Department of Health last week published figures showing 999 ambulance service calls have increased by 6.5 per cent so far this year. Growth is faster than in A&E attendance.

Mr Nicholson called for services to work more closely together to keep patients out of ambulances and away from hospital.

Ambulance Service Network director Liz Kendall said: “The system isn’t working as well as it should and ambulance services are determined to work with other parts of the NHS to improve it. We need to make it simpler and easier for patients to access care and provide a range of services - including GPs, community nurses, mental health services, falls teams and paramedics - 24 hours a day, seven days a week.”