The senate in the Democratic Republic of Congo has voted against a request to lift a member's immunity to allow a corruption related investigation.

Former Prime Minister Matata Ponyo Mapon is being investigated for his role in an agricultural project that failed.

The judiciary had requested that the senate lift his immunity so that he could be prosecuted.

He is alleged to have designed, planned and committed for payment to be made for the project.

Investigators say $200m (£141m) disappeared during the implementation of the project, the Reuters news agency reports.

Mr Mapon has denied any wrongdoing.

He was the prime minister under former President Joseph Kabila from 2012 to 2016.