Mental health bosses have admitted that it has taken almost a year to properly record the performance of a patient referral service.

Norfolk and Suffolk NHS Foundation Trust (NSFT) launched its new access and assessment service in Norfolk last February, which was billed as a single point of contact for GPs' concerned about the mental health of their patients.

Campaigners raised their concerns after figures from a Freedom of Information (FoI) request revealed that the organisation had not hit its referral targets for the last five months of 2013.

Figures showed that 65pc of emergency referrals received an assessment in four hours, only 17pc of urgent referral cases were contacted within 72 hours and 23pc of routine referrals were contacted within the trust's 28 day time limit during December.

However, officials from the NHS trust said they had only been recording access and assessment (A&A) data properly for the last ten weeks and the data from the FoI was inaccurate.

Figures provided by the organisation show that 100pc of four hour referrals and 94pc of 72 hour referrals were assessed on time in February out of more than 700 cases. However, the trust was unable to provide 28 day performance figures.

Emma Corlett, Unison spokesperson and mental health nurse, said the FoI data released to the Campaign to Save Mental Health Services in Norfolk and Suffolk matched the experience that staff working in the service had described.

'There is no escaping the fact that there are simply too many people who need an assessment of their mental health needs, and not enough staff to see them. Staff in access and assessment have been working under unacceptably high pressure for months on end, often at the expense of their own health. There have been a high number of staff who have left the service, and the remaining staff are having to not just juggle an unmanageable workload but also deal with disgruntled and angry GPs and patients, unhappy at delays in getting an assessment. This week assessments are being offered to people referred in January, well short of the 28 day target.'

'It is staggering that after more than a year of service operation NSFT cannot provide data that it believes is accurate. If they cannot accurately monitor demand for the service, how can they determine how many people are needed to work in the service?' she said.

The mental health trust is in the midst of a radical redesign of services to cut its budget by 20pc by 2016. However, figures show that the Norfolk A&A service was running £200,000 over budget by the end of 2013.

Kathy Chapman, director of operations for NSFT in Norfolk and Waveney, said the trust had 'multiple patient recording systems' and was developing a plan to move to one system.

She said that the FoI figures 'predate the introduction of the new reporting system. As such, they will overstate some of the breaches in the access and assessment targets.'

She added: 'The trust has increased the number of staff, introduced evening and weekend clinics, and is working with GPs to ensure referrals are appropriate for an NHS mental health service. As a result of the above measures, there is no referral backlog.'

'Following the launch of the service, it has gone through a period of transition, which has resulted in the use of temporary staffing and overtime for existing staff.'