Norfolk's main hospital had no spare beds for 13 consecutive days earlier this year as a result of extreme pressure, according to new figures.

Fresh fears have been raised about the increased demand on A&E departments after it emerged that two Norfolk hospitals were placed on 'black alert' more times in the first three months of this year than the whole of 2012.

New figures from a Freedom of Information (FoI) request reveal that the Norfolk and Norwich University Hospital was 'gridlocked' on eight occasions between January 1 and April 1, compared with the five times it had zero capacity for the whole of 2012.

The longest period that the Colney site was on black alert was for a total of 312 hours earlier this year, according to the figures released to the EDP.

Norwich North MP Chloe Smith last night said: 'These are worrying revelations and they underline just why the hospital, ambulance service and others need to work closely together to improve services for patients.'

Hospitals are placed on black alert when they have no spare beds and have the option to take measures to suspend elective surgery, restrict GP referrals, and divert ambulances to other acute hospitals to ease pressure.

Figures from the James Paget University Hospital show that the Gorleston hospital was gridlocked on five occasions from January 1 to April 1, but did not declare black alert for the whole of 2012.

The huge pressure on the Norfolk and Norwich University Hospital was highlighted on March 6 when 17 ambulances were queued up outside the hospital because A&E was full. The East of England Ambulance Service also erected a makeshift tent outside the hospital on Easter Monday as a precaution after patients had to wait up to three hours in an ambulance outside the front doors of the hospital.

However, despite the pressures, NHS leaders in Norfolk said delays in admitting patients had been significantly reduced since Easter.

Officials from the Norwich Clinical Commissioning Group (CCG) said the impact of improvements made by local health trusts as part of Project Domino to help ease pressure on the N&N casualty department were having an impact.

At the end of March – when pressures on the NHS were unprecedented - there were 75 handovers taking more than an hour. That figure has dropped to just two in May, they said. The handover of patients from ambulance to A&E within 15 minutes had also improved from 40pc to 56pc.

Jonathon, Fagge, chief executive of Norwich CCG said: 'Pressure on ambulances and A&E is being experienced right across the country, but the data we have shows performance has considerably improved in central Norfolk. This is very much early days and we still have a big, long-term job to improve urgent and emergency care but we are pleased with progress so far.'

A spokesman for the N&N said the hospital had a significantly higher number of admissions earlier this year and a high percentage of them were older and very sick.

'We do not fully understand why the numbers were so high, the long severe winter may be a factor, but we are doing further analysis with CCGs to see what was responsible for this spike of activity,' the spokesman said. The Colney site is investing an extra £2.5m on recruiting 20 extra front-line A&E staff this year.

A spokesman for the James Paget University Hospital added: 'We anticipate and plan for an increase in demand throughout the winter period, however, the middle of March was challenging. We experienced an increase in emergency admissions and a high number of patients with complex medical conditions that required longer lengths of stay. Cases of norovirus and subsequent ward closures led to pressures on bed space, and further delayed discharges which resulted in the increase in black alerts at the trust.'

The Queen Elizabeth Hospital in King's Lynn was on black alert on two occasions in the first three months of 2013, according to the FoI response. Officials from the West Suffolk Hospital in Bury St Edmunds said they did not record black alert incidents.