The Great Interior Design Challenge - Season 4

In the first round of the first heat, the group of amateurs taking on the design challenge are hairdresser Oliver, dog walker Katie and photographer Daniela. They must each transform a bedroom in Regency properties in the grand Pittville estate of Cheltenham. Katie has a nervous time trying to please the client with her use of a controversial peach colour scheme which divides the judges. Oliver's clients aren't too sure about his methods, particularly as he plans to incorporate children's toy hula hoops into the lighting. Daniela has to design for a younger client but can she satisfy a 12-year-old schoolgirl who is after a sophisticated look for her bedroom? All three are each given a surprise item which they have to cleverly incorporate into their scheme within three hours. Who has impressed the judges? One of them will be going home.

In this round of the first heat, retired actor and director Nicholas, marketing assistant James and event stylist Anna must each transform a living room in three Grade-11 listed former workers' cottages in the pretty town of Saltaire. Nicholas is reaching out to his spiritual side as his client wants a Zen-inspired relaxing consulting room, but he may have gone too far with an elaborate Japanese inspired scheme. Anna has to breathe new life into a lack-lustre living room for her client but will she be able to give it a modern masculine bachelor pad makeover? James also has a testing time trying to fulfill a Scandi brief for his homeowner, but can he finish it to his own high standards?

It is the last of the heats and our designers are Richard, an artist from West Yorkshire, Shaida, a freelance makeup artist from Northampton, and Susanne, a solicitor from Loch Lomond in Scotland. They each have the task of transforming a bedroom in imposing Victorian Gothic cottages. Richard is reaching out to his industrial side for his client who wants a chic hotel look, but will his original artwork and use of raw natural materials go down well? Shaida finds that even though her brief from her client matches her own personality, it doesn't mean that her design will be plain sailing. And a peaceful muted zen-like room is a testing brief for paisley pattern-loving Susanne. Challenged by incorporating the homeowners' bulky furniture and technology, Susanne has to draw on all her design charm to impress.

It is the quarter-final and the two designers who have made it to this stage now take on a living room and a sitting room each. Their budgets have increased to ?2,000 and their team has doubled. They have 48 hours across three days but one room must be finished and judged on day two. The designers are in Worsley, trying to transform rooms in Mock Tudor imposing houses. One designer has problems with their waterworks and might not be able to deliver what they have promised. For the other designer, a timing issue might hinder their whole design integrity. Meanwhile, Tom Dyckhoff discovers hidden tunnels beneath the waterways and looks at what life was like when these houses were originally built.

In the second quarter-final, the designers are in the pretty coastal town of Aberaeron in west Wales, a former fishing port. They are tasked with transforming both a bedroom and a study, whilst incorporating the creative challenge - some rope - into their overall scheme. One designer draws on the surrounding Welsh influences to create their schemes, but will the client like the big retro-inspired theme throughout? The other designer finds that a nautical-themed design plan might not be the best option, and judges Kelly and Daniel have to step in. Meanwhile, architectural historian Tom Dyckhoff explores the coastal village and uncovers its far-reaching architectural influences.

In the last of the quarter-final heats, the designers transform two rooms each in glamorous 1930s art deco flats. A possible asbestos outbreak means work is halted for one of the designers. Will they complete their rooms on time? Meanwhile, the other designer might be going too far off brief with a butterfly-inspired effect which dominates heavily throughout the living room. Architectural historian Tom Dyckhoff takes us back in time and shows us that 1930s Streatham, meaning 'Hamlet on the Street', was one of London's most forward futuristic glamorous neighbourhoods.

In this semi-final, two designers transform two rooms in modern town houses in Bristol. Judging them are regulars Kelly Hoppen and Daniel Hopwood and guest judge Michelle Ogundehin, editor in chief of Elle Decoration. One semi-finalist attempts a very intricate hand-painted mural across all the bedroom walls, but can they deliver precision in the ever-decreasing time limitations? Meanwhile, a designer's plans are seriously thrown into question with their demanding client's ever-changing needs. Architectural historian Tom Dyckhoff looks at his favourite buildings in the series, exploring the subject of Modernism, its European origins and this very complex type of architecture.

In the penultimate show of the series, the two designers have to transform two rooms in pretty thatched cottages in Ashby St Ledgers. Both designers are tasked with transforming a living room and a dining room. Judging them are regulars Kelly Hoppen and Daniel Hopwood and guest judge Michelle Ogundehin, editor in chief of Elle Decoration. Both designers unwittingly use the same colour but will this help or hinder their chances with the judges? One designer is seriously out to impress, but will the use of a very detailed and overpowering matching blue print for wallpaper and curtains impress the homeowners or put them off? Will Michelle Ogundehin agree with Daniel and Kelly or put a cat amongst the pigeons? Meanwhile, Tom Dyckhoff discovers the beauty and origins of olde world picturesque country cottage living and the characteristics of thatched dwelling.

It is the grand final. The two top designers have to complete three rooms each in converted apartments in an 18th-century mock castle in Broadstairs. The designers are tackling a kitchen for the first time ever and our designers soon find out that working in older properties is certainly not without its challenges. Judging this epic battle are Daniel Hopwood and Kelly Hoppen, helped and joined by former judge and interior stylist Sophie Robinson. Only one designer can walk away as winner of The Great Interior Design Challenge. Meanwhile, architectural historian Tom Dyckhoff explores the castle and explains the significance of such a beautiful building in British history.