London Underground's top engineer David Waboso

As the director for capital programmes at London Underground (LU), David Waboso is the teacher-turned-engineer who oversees the delivery of everything contained within the network provider’s investment plan, which includes trains, track, signals, stations, power supplies, control systems and all other related works. He handles £1bn of capital investment and a workforce of 2,500 engineers and project managers, in addition to a further 15,000-20,000 people in the supply chain.

In his wood-panelled office, where countless fellowships hang proudly in rectangular frames, the Imperial College civil-engineering graduate explained that rising passenger numbers and a deeptube network are the two biggest factors he is constantly battling with.

The Tube transports more than a billion passengers a year – which is equivalent to the entire population of India. It is one of the busiest metros in the world and, despite a creaking Victorian infrastructure, it is doing its best to meet the expectations of Londoners and tourists alike through its Upgrade Plan.