Andrew Behagg, 60, from food supplier Greenvale, authorised payments in return for lucrative contracts worth millions. The jury of 10 men and two women took five hours and 45 minutes to convict Behagg, of London Road, Chatteris, of one charge of corruption. Judge Nicholas Ainley said: For any case of this magnitude a sentence of imprisonment is almost inevitably passed, and a significant one at that. Behagg is expected to be sentenced on June 22 at the same court alongside Maylam and Greenvales account manager David Baxter, who have both admitted corruption. Thousands of pounds of cash in brown envelopes was handed to buyer John Maylam, who splashed out on lavish meals and stays at top London hotels, Croydon Crown Court heard during the trial. Sainsburys was overcharged by a total of £3.8m by the potato supplier. The extra money went into an account, then some of it was channelled to the buyer. Maylam would incur expenses of £20,000 a month, spending the cash on expensive restaurants and exclusive hotels including Claridges and The Dorchester, the court heard. The crime was uncovered when a Greenvale employee grew suspicious when he was asked to withdraw £5,000 bundles in £50 notes from a small local bank. Jurors heard Simon Forster, a group financial accountant, investigated and found payments were being entered into their financial system as entertaining expenses and then written off as raw materials or storage costs for potatoes at fictitious firms in Spain and the UK. Mr Forster said that when he raised the payments with Behagg - one of the signatories of the account used to withdraw the cash - he was told they were rebates and part of a scheme. He said he was later asked to create a specific account to record other electronic payments so they went through a different track of the system. Mr Forster told the trial that because the local branch of Lloyds they used near their head office in Chatteris was so small, he had to give them prior warning that he was coming to pick up the cash so they could have enough of the high-value notes brought in to pay out. Behagg told the court Greenvale had a two-year contract, worth £40 million a year, to supply 45pc of Sainsburys UK potatoes at the time of the alleged corruption. Describing the size of Greenvale, Behagg said it handles 10pc of the UK potato crop, amounting to 600,000 tonnes a year. Prosecutor Paul Ozin told Behagg during the trial: The truth ... is that you knew perfectly well that these were simply corrupt payments to Mr Maylam to buy you better prices. He said it was highly improper that Maylam was being paid cash out of an account that Sainsburys did not know existed. Maylam, 44, of Bearstead, Maidstone, Kent, who earned millions through the scheme, and Baxter, 50, of Hinstock, Market Drayton, Shropshire, were arrested after the companys external auditor was alerted. Following the verdict, Produce Investments, the owners of Greenvale, said: We instigated this investigation and have since then introduced new procedures to make sure that such abuse can never happen again. Our relationship with Sainsburys is now on a footing as before and we continue to be one of the largest suppliers of potatoes to shoppers all over the country. A Sainsburys spokesman said: This was an unacceptable and calculated crime against Sainsburys of a magnitude never experienced in our history. We are pleased that justice has been done with todays verdict and we would like to thank the police for their thorough investigation that led to the conviction of John Maylam and David Baxter in 2011 and Andrew Behagg today. Todays verdict sends a very clear message to anyone who behaves in this way that there are consequences to their actions. We demand the highest standards of all our colleagues and suppliers and Sainsburys code of conduct clearly details how we expect them to behave, and is reinforced by our confidential whistle blowing line.