James takes model aeroplanes to a new level when he tries to make a full-size Spitfire out of Airfix. The venture soon hits problems when it becomes clear the giant 36-foot pieces may not be strong enough, and nobody knows how they will fit together. James hopes he can enthuse a group of reluctant teenagers to help him pull it off - but he soon realises he has another big battle on his hands in convincing them it is a hobby to be proud of.

James tries to make a garden entirely out of Plasticine and then enter it at the Chelsea Flower Show. He persuades thousands of members of the British public to help make the thousands of Plasticine flowers he needs, but will it be enough to persuade the guardians of the world's most prestigious horticultural event to let him make a garden with no real flowers in it?

James joins forces with Edwina Currie to build a full-size bridge from nothing but Meccano. Top engineers pitch incredible designs, but the project soon careers out of control when the Meccano does not arrive and James realises it will take longer to build than he imagined. A last-minute accident also means that James’ bridge may never see the light of day. Please note, this version may differ slightly from the UK TX version.

James attempts to build the biggest Scalextric track in the world, nearly three miles long, on the site of Britain's oldest grand prix track at Brooklands in Surrey. The track will have to go through people's gardens, over ponds and rivers and even negotiate a business park. Who will win the race of the century, the plucky locals or the team of Scalextric experts?

James attempts to build the longest ever model railway track, a whopping ten miles long. Stretching from Barnstabe to Bideford along a disused railway line, the track must survive the attentions of local vandals if the team is to succeed. Matters aren’t exactly helped by the model train’s top speed of 1mph! Please note, this version may differ slightly from the UK TX version.

With the help of an army of volunteers, James attempts to build the world’s first full-size house made entirely out of lego bricks. He even tries to plumb in and fearlessly road test a Lego loo, take a dip in a Lego bath and rest his weary head in a giant Lego bed. Please note, this version may differ slightly from the UK TX version.