The former head of operations at the Royal Horticultural Society, pleaded guilty to one count of fraud by abuse of position and two counts of conspiracy to steal from the organisation over a ten-year period.

Stuart Medhurst, 54, appeared in Southwark Crown Court on Wednesday and is reportedly going to be sentenced next year after the conclusion of the trials of his two co-accused: Shaheen Kadri, 43, and Elaine Summers, 53, neither of whom used to work at the RHS.

Kadri and Summers both plead not guilty to a single charge of conspiracy to steal each. Their trials are scheduled to take place in July 2016.

Medhurst, who left RHS in 2013, originally appeared in Westminster Magistrates Court on Wednesday 28 January, accused of stealing £43,000 worth of goods and services between 2007 and 2014. He was also accused of giving £317,110 of the charity’s money to Kadri between January 2004 and January 2015, with Summers receiving £360,859 over the same period.

Sue Biggs, RHS director general said: “Over the last three years we have been conducting in-depth audits across all our work and implementing more robust measures and controls to protect the RHS. This incident demonstrates how important this work has been and today we’re in a much stronger and more robust position to ensure unacceptable activity could not take place within the RHS. 

"Stuart Medhurst abused his previous position as a manager at the RHS with sophisticated and calculated fraud. Losses to the revenue of the RHS have largely been covered by insurance.

“We routinely monitor our work and look at all our procedures and controls to safeguard the RHS, its employees and volunteers and the interests of people who support us. We conduct in-depth audits across all our work and have implemented enhancements to our financial controls to give even greater protection to the Society’s funds.”

According to the RHS’ accounts, the organisation’s income in 2014 was £71.9m, down from £81.3m in the year before.