The firm was founded in 1921 by Thomas Penberthy Bennett and rapidly grew into a leading architectural practice, having established a reputation for innovative design and technical excellence. During these early years of practice, “TP” was also Head of the Northern Polytechnic Institute of Architecture.

Initially the office was based in Bedford Row, Bloomsbury, but within fifteen years the firm had grown to more than 70 staff and two additional partners, requiring larger premises in Bloomsbury Square.

An early landmark building was Eyre Court (1930) a speculative apartment block on the Finchley Road, using innovative apartment layouts and features in contrast to existing mansion blocks, rapidly setting a benchmark for other contemporary and future developments. Further commissions followed, including developments such as Dorset House in Marylebone Road (Grade II listed), speculative offices such as Great Westminster House on Horseferry Road, and Bennett's own favourite, the Saville Theatre (again Grade II listed), one of several notable commissions that had an artistic collaboration with Gilbert Bayes RA, resulting in bas-relief sculpture becoming seamlessly integrated with the architectural design. The Doulton Headquarters building in Lambeth was another fine example and the whole Art Deco facade, including the bas-relief, was made from majolica by Doulton. The main frieze was salvaged and is displayed in the V&A Museum.

TP believed firmly in the strong relationship between art and architecture and encouraged the whole firm to follow his lead in sketching from life in order to hone drawing skills and the appreciation of line and proportion. Life classes were a feature of the working week within the office well into the 1960’s.

Bennett is sometimes credited with being the originator of the modern speculative office building in London. At the very least, he was certainly in the first cohort and in early commissions such as Great Westminster House, a stand-alone 250,000 sq ft speculative development, he established the now familiar principles of large floor plates, virtually column-free space within a framed structure; modular grid and careful positioning of cores that would allow future tenants to lease whole or part and fit it out for their own occupation.

During the Second World War, Bennett left his Partners in charge of a firmly established practice while he took several public posts, including Controller of Bricks (1940), Director of Works in the Ministry of Works (1941) and Controller of Temporary Housing (1944) which he held concurrently until the end of the war. This ethos of social responsibility and public service culminated in his appointment in 1947 as Chairman of Crawley New Town, delaying his return to full time private practice until 1960.

During the 1950’s and 1960’s the practice flourished and many major commissions were undertaken, including the Poultry Market at Smithfield (again Grade II Listed).

On his retirement in 1967, Sir Thomas left a strong partnership with his own personal values fully engrained in the culture of the company. Until 1979 it was led by his son Philip with a talented team of partners who had trained under Sir Thomas's exacting eye. During this time additional offices were opened in Reading, Brentwood, Bootle and the Middle East, as well as the main office at 262 High Holborn, designed by the firm for Pearl Assurance.

During the 1980's tp bennett was quick to recognise the potential of new technology and the increasing efficiency of IT and was in the vanguard of those firms making a commitment to CAD. It was at this stage that the regional offices closed and consolidated at 262 High Holborn, which became and remained the principal office until the move to One America Street, Southwark in 1998. The practice grew considerably during the 1980's and in 1989 experienced a generational shift from the old guard of longer-serving partners, who had worked alongside or under “TP”, to a new generation.

This younger generation, including four of the current principals, worked to maintain the strength of the practice and in the decade since the move to One America Street, has achieved business growth and an enhanced design reputation across an increasing breadth of sectors. The practice attracts talented architects from around the world and opened offices in Moscow in 2006 and Abu Dhabi in 2008. In 2004 SEF, (previously Stilman Eastwick Field) was incorporated into the practice, strengthening specialisms such as healthcare, education and social housing. tp bennett became a Limited Liability Partnership in 2005 to reflect its growing size and through a broader base of ownership to continue to attract, encourage and retain talented professionals.

Most recently in January 2010 Engle merged with the practice to create a powerful new retail and regeneration consultancy.

True to Sir Thomas's founding principles, the practice continues to be design-led, responsible, intelligent and collaborative in its approach to Architecture. The practice moves forward in the key disciplines of Architecture, Interiors and Planning across a variety of sectors, including all those explored by “TP” himself, such as housing, offices, healthcare, education, leisure and retail, alongside more recent ones such as transportation and student accommodation.