The company contracted to provide court interpreters has failed to reach its performance target after a year, new statistics have revealed, leading to delay in thousands of court cases.

Figures released by the Ministry of Justice show that the performance got worse in the first month of this year and that the rate of complaints about the service have risen since August.

In a procurement process that has been heavily criticised, the MoJ awarded the interpreting contract to Applied Language Solutions, which was subsequently bought by Capita and is now called Capita Translation and Interpreting (CTI).

From the date that the contract started, on 30 January 2012 to 31 January 2013, CTI’s overall success rate was 90%, against a contractual target of 98%.

During the first year, CTI received 131,153 requests for language services covering 259 different languages. Of these, 14,823 (11%) ‘were cancelled by the requesting customer’ – that is either HM Courts & Tribunal Service or National Offender Management Service.

Of the remaining 116,330 requests, 104,932 were fulfilled or the requesting customer failed to attend – a success rate of 90% over the whole period.

In its statistical bulletin, the MoJ says that ‘presenting a single success rate does not provide the whole picture on the changes in the operation of the contract over the first 12 months’.

In the first month of the contract (January 30 to February 29, 2012), CTI fulfilled 67% of requests; in the second month this increased to 81%, and in the third month it fulfilled 90%. For the remainder of 2012 the success rate ranged between 92 and 95%.

However, by the end of January 2013 the success rate had fallen to just over 86%. The MoJ information says that this fall coincided with the contractor reducing the mileage rate paid to interpreters.

During the year, there were 6,417 complaints recorded relating to completed requests made, the majority due to the interpreter not attending or attending late. The data shows that the complaint rate (the number of complaints divided by the number of completed requests) increased between August 2012 and January 2013.

Courts minister Helen Grant said: ‘There has been a dramatic improvement in the interpreter contract since the early months, with the vast majority of bookings now being completed and a major reduction in complaints. Our changes have saved taxpayers £15m this year.

‘We are aware performance dipped very slightly this January when changes were made to interpreters' travel allowances and we are taking steps with the contractor to address this and drive further improvement.’