Leighton is a Director of Ext. Arch. and a Chartered member of the Landscape Institute. He brings a wealth of domestic and international experience across all sectors. Based in the London office Leighton is a talented designer and conceptual thinker Leighton and is currently overseeing Ext. Arch's master planning work in the UK and overseas. He is also responsible for the management and delivery of the practices current work load from concept design to implementation.

Leighton was CBA's London Director and was responsible for delivering a wide variety of park, public space, civic and heritage projects both in the UK and internationally. Significant works Leighton undertook at CBA included leading Stonehenge Environmental Project from Planning to Implementation and winning an international competition for a new city district in Beirut call the New Waterfront District. Key projects leighton was responsible for included Lordship Recreation Ground, Tottenham; Beirut Western Marina, Beirut; Broadwater Farm Learning Campus, Tottenham; Hampden Fields in South East Aylesbury; Freeman's Reach, Durham; Westminster Lodge, St Albans; final phases of the Old Royal Navel College in Greenwich and numerous others.

Leighton role at MSP was originally as UK project management led and encompassed a wide variety of tasks varying from design and project management to practice administration and business development. Leighton led teams to create, develop and deliver a wide range of project and successfully led MSP's team who won a 32 acre landscape project associated with a new hospital in North Vienna (Krankenhouse Nord). Leighton also led teams on the Hauptbahnoff Project in Central Vienna, Barker Park in Finland, Northumberland Park (Tottenham FC stadium) in London, Baskerville Wharf in Birmingham, Doha Compound in Qatar and numerous others.

During Leighton's 5 years at LBA he rose from Senior Landscape Architect to Senior Associate leading some of LBA's most iconic projects. His work spanned all scales and sectors from landscape master plans such as for the regeneration Grahame Park in Colindale, the Aylesbury Estate in South London, Bermondsey Spa regeneration areas, and South Kilburn Masterplan to public realm and urban regeneration projects such as Shoreditch Park, Hackney; Larkhall Park, Lambeth, Heybourne Park in Colindale, and student accommodation for Ramsey Hall for UCL in London.Leighton involvement in some of LBA's key housing projects such as Pimlico Village, London, the Bolanachi Building, Southwark and landscape regeneration of estates such as the Pembury Estate and various others residential projects has given him a complete and full understanding of how to design, detail and progress through planning complex urban regeneration schemes. Leighton looked to innovative where possible and the consultation techniques he developed to involve and prosper local communities involvement in the design and deliver process, such as in the Aylesbury Arts, Sports and Environment Project, delivered truly ground-up design that related directly to community needs and requirements.Design was central to all project Leighton undertook at LBA and his contribution to staff mentoring and business development coincided with one of the most successful periods in LBAL history.