Mike was appointed Commissioner in September 2015 overseeing the largest integrated Transport Authority in the world.
He joined London Underground (LU) in 1989 and became chief operating officer in 2003.
He left London Underground to run Heathrow Airport during a massive transformation and passenger improvement programme.
Mike returned to London Underground as managing director and was responsible for operating services with more than one billion journeys every year and for leading the largest line upgrade and investment programme the Underground has ever seen.
He improved the reliability of the Tube network across all lines and led the successful delivery of the services to support the Olympic and Paralympic Games in 2012.
He was also responsible for the operation of Docklands Light Railway, the Trams and London Overground as well as the Emirates Airline Cable Car.
Now, as London's Transport Commissioner, Mike is ultimately responsible for a multi-million pound investment programme and the delivery of transport services across London, with some 13 million passenger journeys every day.
Ian joined TfL on 1 September 2015 as Chief Finance Officer (CFO) and became Interim Managing Director Finance on 1 October 2015. In February 2016 Ian was appointed to a single CFO position, which combined the two former roles.
He is a Fellow of the Institute of Chartered Accountants in England and Wales and has extensive experience in the private sector and in publicly-funded businesses.
Ian joined from Ordnance Survey where he was CFO. Before that he was at LOCOG (The London Organising Committee of the Olympic and Paralympic Games), where he headed a company to deliver a post-Games legacy for community sport - The Join in Trust. He was also CFO at Eurostar for more than 10 years.
Ian is a fluent French speaker having previously spent several years working in France for PWC (where he met his French wife Catherine), Elf and Courtaulds Textiles.
Howard joined us in September 2006 having been head of legal and procurement at the Greater London Authority since 2001.
He was previously director of legal and secretariat at English Heritage and has worked in local government.
He is a barrister with wide experience of managing legal, secretariat and corporate governance functions.
His responsibilities include legal, corporate governance, information access and compliance, secretariat and internal audit.
Leon joined us in April 2011 from FirstGroup, where he had been a director of the UK Bus Board since 2000.
For several years Leon owned and ran his own bus company, which grew to be the largest private sector bus company in London prior to the privatisation of London Buses. He sold the company to FirstGroup in 1998.
He oversees TfL's responsibilities for the safe and efficient running of London's buses, taxis, river services, the road network, congestion charging and Santander Cycles.
Michèle joined us in 2000 as co-director of Congestion Charging.
She started her career at the Greater London Council and became a chartered civil engineer through their transport planning graduate scheme.
She later went onto work for Halcrow Fox, where she became a board director.
In 2007 Michèle became Managing Director of Planning. She was responsible for leading the planning strategy on the future transport needs of London, coordinating the implementation of local plans and borough partnerships, and developing major scheme initiatives.
In February 2015, Michèle left Planning to become the Managing Director of Crossrail 2 and is now responsible for developing Crossrail 2 and gaining funding and powers for it.
Vernon is responsible for TfL's customer and technology/data strategies and their delivery. These put customers at the heart of the organisation's operations.
This includes accountability for fares and payment operations, contact centres, customer information, marketing and customer insight, media relations, public affairs and travel demand management.
He focuses on how TfL can use technology and open data to deliver better journey on public transport and the road network, and enable TfL's employees to provide better customer service. He also leads on supporting and partnering with the capital's thriving tech sector.
Vernon led the successful pan-Government and transport industry marketing and communications strategy for the London 2012 Games, the largest integrated campaign of its kind ever undertaken.
Before joining TfL in 2007, Vernon spent 10 years at the Financial Services Authority (FSA) and 18 years at the Bank of England in a variety of banking, regulatory, corporate and communications roles. This included leading the FSA's national work to improve the financial capability of consumers.
Vernon is on the Board of the London Transport Museum and is a member of an Advisory Group to Marston Group, the largest privately owned specialist UK company in the field of civil and High Court Enforcement. He is a Fellow of the Chartered Institute of Logistics and Transport.
Mark Wild joined TfL in June 2016 from Australia where he was Special Advisor to the Minister and Secretary of The State Government of Victoria. Just before that he was Chief Executive of Public Transport Victoria, the integrated transport authority based in Melbourne serving a population of some six million people.
His near-30 year career in transport has included running the world's biggest tram network and large suburban railway and bus services. He has also successfully managed large capital and maintenance programmes, vastly improved customer satisfaction and implemented a complex new ticketing system.
He also formerly worked on a number of major projects in London, including the introduction of modern signalling on the Jubilee and Victoria lines.
Chief Officers' expenses are published quarterly on the Chief Officers' expenses page.