With his middle-class upbringing, university education and frugal lifestyle, Michael Seed made an unlikely member of the Hatton Garden gang.

But his expertise in electronics, honed to defeat sophisticated security systems, brought him together with some of the most notorious figures in the London underworld.

The son of a university professor, Seed, 58, grew up in Cambridge, where he made frequent visits to his mother in her 90s, until Flying Squad detectives came through his door in an early morning raid on March 27 last year.

Officers – who made simultaneous searches of Seed’s mother’s large house in Cambridge and his brother’s ground-floor flat in Forest Gate, east London, found £143,000 worth of jewellery, gold ingots and gems stolen in the Hatton Garden raid.

Hatton Garden Safe Deposit company raid
Gold and jewellery stolen from Hatton Garden found in Michael Seed’s flat (Metropolitan Police/PA)

Seed was not known to police three years earlier when he was photographed twice meeting another member of the gang in the weeks after the £14 million burglary.

As a teenager, he took A-levels in physics, chemistry, maths and geology at a secondary modern school outside Cambridge before working in an electronics factory making parts for submarine detectors.

“I have always had an interest in electronics”, well-spoken Seed told jurors during his trial at Woolwich Crown Court. “It was a passion of mine.”

Seed studied physics and electronics at Nottingham University, where he “enjoyed recreational drugs” and “used to take LSD every weekend” before his one previous run-in with the law.

In 1984, aged 24, Seed was handed a three-year prison sentence for supplying controlled drugs of Class A and Class B after selling 10 LSD tablets and some cannabis to a friend.

Hatton Garden Safe Deposit company raid
Michael Seed (left) was unknown to police when he was pictured meeting John ‘Kenny’ Collins (Metropolitan Police/PA)

He was released after serving 21 months and got his one-bedroom council flat in Islington for £13 a week, where he lived up until his arrest, when his rent had risen to £105.

Seed told jurors he worked fixing televisions, video recorders and computers before moving into the jewellery trade in the mid-1990s.

“It’s purely a thing for money,” he said.

“I have never had an interest in jewellery or even a liking for it.

“I got into the recycling jewellery thing because I’m good with my hands.”

He said it was around this time when he first met career criminal Brian Reader, 80, who was once jailed for laundering gold bullion from the £26 million Brink’s-Mat heist in 1983 – in a cafe in Hatton Garden.

Seed said Reader introduced him to John “Kenny” Collins, 78, and Danny Jones, 64, but claimed he did not know Terry Perkins, who died last year aged 69, one of the men convicted for the £6 million Security Express cash robbery in 1983.

Planning for the job began as early as 2012 and Seed played a crucial role in securing entry to 88-90 Hatton Garden, where it is believed he disabled the lift to allow access to the safe deposit company in the basement and defeated the alarm.

He was one of two men to crawl through the hole drilled through the vault wall before looting gems, gold, jewellery and cash from 73 safe deposit boxes over the 2015 Easter bank holiday weekend.

Prosecutors pointed to electronic equipment found on the bedroom workbench of his cluttered flat to highlight his role as the gang’s “alarm man”.

Two micro SD memory cards containing encrypted data were found hidden and wrapped in tinfoil.

Experts found they stored family photographs but could not crack the second level of encryption, while a third SD card found in Seed’s wallet had brochures for safes.

In the living room, officers found 280 magazines, books and newspaper clippings about electronics, telephony, surveillance and jewellery.

Hatton Garden Safe Deposit company raid
Basil disguised himself with a mask, hat and wig during the Hatton Garden burglary (Metropolitan Police/PA)

The library included a book about listening devices, an article about GCHQ eavesdropping on phone calls, a book entitled “How to build a gas fired crucible” and a telecommunications dictionary marked with a BT stamp.

Police seized at least five computers and an analysis of Seed’s search history showed he was looking for the “price of UK gold” in the run-up to the Hatton Garden burglary.

In the days following the raid, Seed had looked at BBC news articles including one headlined: “Who were the jewellery heist raiders?”

He had 150 pages of handwritten notes containing phone numbers, addresses, calculations and electronic diagrams, while translations of foreign words suggested he was learning Portuguese.

Unemployed since 2009, Seed has never declared or registered any business in the UK, never declared or paid tax on any earnings and did not receive benefits.

He had one Santander bank account, which he used mainly to buy tools and electronic equipment online.

Just £9,500 came out between 2010 and 2018, and his rent was regularly paid into a Post Office account in cash.

“I have always worked in the black economy,” he said.

“I don’t pay tax, I don’t claim benefits. I don’t have an extravagant lifestyle.

“I don’t have a car, I don’t have a vehicle, I don’t really go out more than once a week.”

Seed gave a confident performance in the witness box and shared jokes with his barrister or dock officers when the jury were not in court.

He denied electronic devices were for use in the high-end crimes, claiming infrared sensors and buzzers were part of a system set up to frighten pigeons from his balcony.

Seed said he also used to build mobile phone jammers, including one prosecutors say could have been used to block alarm signals, to sell on his Spitalfields market stall in east London before the advent of 3G in around 2002.

“It’s just a fun thing if you’re into electronics,” he added.