The Great Interior Design Challenge

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.