Throughout the history of architecture, there have been many divisive periods that will have enthusiasts arguing long into the night.
However, one that has attracted perhaps more debate than any has been the brutalist period that dominated the new buildings in the British skyline throughout the 1950s, 60s and 70s.
Concrete based and almost fort-like in their design, brutalist buildings were used for a range of different purposes throughout the decades, with apartments, public buildings and commercial properties all receiving the unapologetic and blocky designs.
It is the latter that has stood the test of time best though, and there are a number of office blocks around the UK that still proudly display the style of the time. We look at the top five brutalist offices across the country.
Pinnacle Building, Leeds
One of the most defining factors of the brutalist period was the way in which the towering concrete blocks dominated the skylines in which they were situated. For no building is this more true than The Pinnacle Building in Leeds.
The office block is visible from almost all parts of the city, and despite the fact it stands at just 80 metres tall - far smaller than many of the other examples from this period - it is a commanding force among comparatively smaller buildings throughout the city.
Despite the fact it recently lost its title as marginally the tallest building in Leeds to Bridgewater Place, it is still as prominent as it was when first completed in 1973.
Primarily an office block, the 20-storey building also comprises a number of retail units in its bottom floors.
Sampson House, London
Situated in Southwark, Sampson House is one of the more unusual examples of brutalist work that can be found in the UK.
Unlike many of its compatriots, Sampson House is actually not particularly tall. It is perhaps the one building on this list that really encapsulates the fort-like essence of the entire period, though, with much of the focus on the blocky, almost pyramidical shape that has seen it stand the test of time as opposed to its height.
Built in 1979, it takes brutalism to the extreme, with very minimal use of glazing at street level and extensive use of metal cladding in its upper reaches.
It is also the UK home of technology giant IBM, which makes use of the structure's extensive and unique underground floors. The basement levels host the company's many data centres.
Located near the Tate Gallery, Sampson House is definitely one for architecture fans to visit, as it offers a design far removed from anything else in the country.
Centre Point, London
Once described as having 'elegance worthy of a Wren steeple' by the Royal Fine Art Commission, Richard Seifert's London office block is a rare example of a protected brutalist building. It has been a Grade II listed building since 1995 and is considered something of a landmark in the capital.
A towering mass of concrete and glass, the 117-metre tall structure is now home to a range of different business, including a restaurant and a free viewing platform on the top floor.
These days, the building is used by the Confederation of British Industry as its headquarters in the UK, as it has been since 1980, and despite it having sat empty for many years after its construction, it is now considered something of a treasure.
It has also won a number of different awards throughout its 47-year legacy in the London skyline, including the Concrete Society's Mature Structures Award in 2009.
Bracken House, London
Originally the home of the Financial Times newspaper, Bracken House was constructed in the 1950s by Albert Richardson. Completed in 1959, it was seen as something of an iconic home for the British broadsheet.
It comprised an H design with a central unit which originally housed the printing facilities of the newspaper. However, since the 1980s, the building has seen some drastic changes.
Changes in the way newspapers are printed saw the Financial Times relocating to Docklands, and the building was sold to Obayashi, with the original printing area demolished and redesigned as dealing floors.
Although internally everything was gutted and replaced during this period, the building actually managed to retain much of its late-50s charm externally, with the concrete structure punctuated with iconic bronze fittings that hold the many windows in place.
102 Petty France, London
Located in Westminster, 102 Petty France has been somewhat politically important since it was completed by Fitzroy Robinson & Partners, with Sir Basil Spence in 1976.
Despite standing at just 56-metres and being somewhat dwarfed by many of the other buildings that surround it in central London, the structure is perhaps one of the best examples of brutalist architecture in the whole country.
Its concrete base and bulging upper floors are as garish and blocky as architects of the time dared to be, and it really shows the creative side of this time period off perfectly.
Home to the UK Home Office for the first few years of its life, the 14-storey building has since been taken over by the Ministry of Justice, and remains a favourite site in Westminster.