Cockney David Exley has called time on a 25 year career at Clifford Chance in a management role which he said “never really existed”.

The 63-year-old failed his 11-plus so relied on a combination of East End charm and cheek to secure his job as head of facilities management.

After training as an electrician and air conditioning fitter he penned a brash, direct letter to bosses at the law company insisting they needed his skills as they set up a new office base in the City.

The self-styled “Wapping boy does good” will spend his final working day on the estate tomorrow, Friday December 18.

“I said to my colleagues at my leaving do, my job’s done,” said David, who oversees lettings and re-lets within Clifford Chance’s base at 10 Upper Bank Street.

“They gave me the job that never existed and I’ve been here 25 years since. People say you’ll know when it’s time and I couldn’t leave at a better time. I couldn’t have imagined a career which started out with no such expectations at all.”

Roll the clock back more than a quarter of a century and David was a qualified electrician courtesy of an apprenticeship at Trollope and Colls, the firm behind the building of the Stock Exchange tower in the City.

His dad had been a docker but David was inspired by the “magic” of an electrician’s role.

“I was taught a few lessons being a Cockney chap from the East End, and a bit of a lad – they taught me I shouldn’t gamble a week’s wages away in one day, which was 10p an hour, when we used to play cards at lunchtime. But I wanted to go all the way.”

His competitive streak meant he switched careers aged 23, and trained to become an air conditioning engineer.

Then followed stints at the BBC World Service and Lehman Brothers as engineer and building services manager.

In 1990, Clifford Chance [then Clifford Turner and Coward Chance] had its sights set on 200 Aldersgate Street, moving from nine separate properties into one building.

“I was desperate to move on from where I was at Lehman Brothers and I knew they would look at us and how we managed things. I thought ‘let’s chance my arm’. I wrote to them and told them I knew the building was two and a half years away from being completed, and told them they needed me.

“You can choose to stay in one room or push against a door to see what’s in the next location.”

He was part of the team as Clifford Chance moved to the estate in 2003. Since then, the building has been called “The Green Giant” after David’s efforts helped it become the first in Canary Wharf to get the Breeam Excellent rating for sustainability.

More recently, he has overseen the switch of more than 27,000 light fittings for LED lamps “to make the giant even more greener”.

In his role he has also worked closely with Broad St ABC, his former boxing club in E1, and various apprenticeship schemes.

“I was trying to bring people from the other side of the track who might live in the area and have a fear of the towers and flash bankers in Canary Wharf ,” he said.

In 2008 he penned his first book, From Wapping To Canary Wharf to record his quirky story of success. “I might add a couple of chapters to the existing book.

“You’ve only got one life but I didn’t realise there would be so much interest in it.”