The boss of a multimillion-pound scrap metal business in North Woolwich has been warned he faces jail after he was convicted of handling stolen jewels worth tens of thousands of pounds.

Charles Matthews, 55, stashed 50 diamonds, carved emeralds and other jewellery which police discovered was stolen in the ceiling of his office at London City Metals In Factory Road.

He was found guilty of handling stolen goods by a jury of seven men and five women at Southwark Crown Court on Friday, after the hoard was found by detectives in August 2015.

It included 50 diamonds valued at about £48,750, a pair of emerald earrings estimated to be worth £31,500 and a sapphire, ruby and diamond-encrusted bracelet valued at £8,750.

Matthews, known as “Chick”, had claimed the jewellery haul was given to him in a wooden box by a friend called James Tibbs, whom he had known for most of his life, but he had no idea it was stolen.

A diamond examining kit was also found on the site, which Matthews claimed belonged to his father.

He told jurors Mr Tibbs asked him to keep the jewellery in the safe of the scrap metal business over the Christmas 2014 period.

Matthews said it was hidden in a black bag in the ceiling because the time-delay safe broke and he decided not to have it fixed, as his business became mainly cashless following the 2013 Scrap Metal Dealers Act.

The Act means dealers can only buy scrap metal by cheque or electronic money transfer.

Before that, Matthews estimated around £50,000 to £100,000 in cash was delivered to the site each day and the business paid up to £300,000 in cash per week for metals.

His family has been in the scrap metal business since the 1950s and the company, run with his brother and son, turned over between £10 million and £12 million in 2015 and employed some 35 staff, Matthews said.

Prosecutor Philip Evans QC told the hearing Matthews was convicted in November 2017, while on bail for the jewellery offence, of racially aggravated common assault and beating.

For that, he was handed a suspended jail sentence and told to carry out unpaid work.

Judge Joanna Korner QC bailed Matthews until the sentencing on Friday but told him he must stay at his home address under a curfew and report at a police station daily.

She said: “I’m going to sentence him on the basis that he was handling high-value uncut diamonds, and the rest, and that’s an inevitable prison sentence.”

He was also told to surrender his passport and ordered not to apply for international travel documents.