Series 4

The Bake Off returns and for the first time ever, the tent welcomes a baker's dozen to do battle. Mel Giedroyc and Sue Perkins coax them through their baking trials, all the while under the scrutiny of the inimitable judges Mary Berry and Paul Hollywood. With a range of baking styles and personalities, the Bake Off tent is packed with the best amateur bakers from around the country; from space engineer to student, teacher to dentist, psychologist to carpenter. But after ten weeks of whisking, crimping and piping, only one can emerge victorious. This time, nobody is safe because Mary and Paul may decide to lose not one but two bakers at any time. The judges set the signature challenges as true home baker staples so that they can immediately see the bakers' personalities and their range of skills and ideas, setting them apart from each other. The first challenge is a sandwich cake. While this might seem simple, there is a difficult choice to be made between going for the classic or being experimental. Something tried and tested might not stand out, but going for ambitious flavours and ideas could miss the mark. Mary's first technical challenge is for angel food cake, which is not the bakers' idea of heaven as they attempt to follow the bare bones of the recipe, which proves to be a recipe for disaster for some. The showstopper explores all things chocolate, and is their final chance to secure their place in the Bake Off and save them from being the first to leave the tent.

One week down and the remaining 12 bakers have 9 weeks and 27 gruelling challenges to get through before they can be crowned Winner of the Great British Bake Off. But having survived cake, now they battle bread. Knowing that Paul will be watching their every move and prove, they must bake 36 perfectly thin and crispy signature bread sticks, a technically tricky English muffin, and the most outrageous showstopping loaves of bread ever seen on television... from a Christmas wreath to a proud peacock and a psychic octopus. As the bakers try to perfect their breakfast muffins, we explore their rise in popularity in Georgian England, initially distributed by a network of muffin men, now immortalised in the famous nursery rhyme. Mel and Sue try to help but instead leave chaos in their wake, as Mary and Paul use the challenges to find out what type of bakers they are and exactly how far they can push their baking skills. They are looking for real talent and natural instinct, creativity and baking brilliance. At any time, two bakers might be asked to leave, making this year tougher than ever before... nobody is safe.

It's week three, and the heat in the kitchen is already too much for some, as the remaining 11 bakers get ready to deal with desserts. Mary and Paul are upping the ante. Having survived cake and bread, this is the first week we see the bakers having to multi-task across several different baking skills at the same time; a signature trifle combining biscuit, cake, jelly or custard in perfectly distinct layers; a technically difficult task of making floating islands, which result in various forms of unrecognisable landmass by the end of the bake and a showstopper that pulls out all the stops, getting the bakers to juggle 24 petit fours that the judges might finally deem acceptable. They are taking no prisoners, and for the first time ever, there's a baking burglary in the Bake Off tent and it becomes a crime scene. Mel explores the origins of the trifle and discovers how it was transformed in the Georgian era from an elitist dessert for the aristocracy to a dish that was accessible to the masses.

It's week four in the tent and the baking is getting serious, as the remaining bakers put on their pinnies to pimp up pies and tarts. From the country's oldest known cookbook, we discover the almost 700 year old history of the English custard tart. It might once have been popular at the decadent court of King Richard II but it is now a technical challenge in the Bake Off tent, one which causes more than the intended wobble for the bakers. Starting with what should be a home baker staple, their signature double-crusted fruit pies present a challenge to even the most experienced bakers, let alone the one baker who has a deep-hatred of all things fruit, and the showstopper sorts the bakers from the boys, as they set about making a filo pie centrepiece. Mel and Sue come to their aid as the bakers' nerves are stretched tighter than the filo pastry they are making from scratch.

Almost halfway through the Bake Off and the remaining eight bakers are faced with biscuits and traybakes. First up, a Signature Challenge that requires them to do something apparently simple - produce their favourite traybake. The bakers offer Mary Berry and Paul Hollywood their twists on everything from bakewells to banoffees and brownies. Next they face the thinnest Technical Challenge ever devised on Bake Off - the French classic tuiles, biscuits formed into fragile rolls and decorated with delicate designs of piped chocolate. And finally, a Showstopper of epic proportions as the bakers make 'biscuit towers'. Mel and Sue follow the trail of biscuit crumbs as the bakers produce architectural feats inspired by everything from ancient Japanese civilization to one of time travel's most feared enemies. Meanwhile, we discover how the Tottenham Cake, a pink, iced traybake produced by the Quakers of North London, became a match day treat at White Hart Lane.

It is week six in the tent and time for sweet dough week - but will it prove bittersweet for the bakers? They kick off with a signature tea loaf. Most of the bakers choose to make something connected to home, so Mary Berry and Paul Hollywood are presented with everything from locally sourced loaves from Yorkshire and Oxford to Devonshire-inspired panettone and Welsh bara brith. Meanwhile we explore the history of the Sally Lunn, and the story of the torta negra - the well-travelled tea loaf that creates a taste of Wales in the middle of Patagonia. The bakers face Paul's most twisted Technical Challenge yet and a Showstopper that draws on all of Europe for inspiration, creating 36 sweet European buns - from Swedish cinnamon buns to German schnecken and French brioches. Over halfway through and the stakes are high... but will their dough rise too?

With only six bakers left in the tent the stakes are getting higher and this week they face pastry. The remaining bakers bring the old fashioned suet pudding bang up to date, banishing nightmares of stodgy school dinners for good with their range of creative signature suet puds, from 'spotted dick with a kick' to fig roly-poly. Delving further into the history of suet takes us to the Isle of Mull, where the clootie dumpling has been at the heart of the community for centuries. The technical challenge this week proves to be hell on earth, as the bakers are set one of Mary's choux pastry recipes and they must make eight perfect religieuse. These are delicate choux buns filled with crème patissiere, topped with shining ganache and balanced delicately one on top of the other. As they reach the end of their pastry marathon, the bakers reach the showstopper and must make three different types of perfectly puffed pastries. One type must be filled, another must be iced and the third is up to them. From palmiers to cream horns, they have just four hours to impress the judges. On your marks...get set...BAKE!

It is the quarter final and there are just five bakers left. In the last seven weeks they have been tested on normal cakes, breads, pastries, pies and puddings so the judges are upping the ante. This week's challenges test them on how they cope working with unconventional flours and unusual desserts which push their creativity to the max. For the signature challenge, the bakers must make a loaf using non-traditional wheat flours, encouraged instead to use the rarer flours such as spelt, rye, potato or tapioca flours. Whilst the bakers get busy with their loaves, the programme explores the history of the National Loaf. This culinary creation was borne out of necessity during World War Two, when the Ministry of Food developed a flour to make imports go further and keep the nation healthy in times of rationing. The technical round sees the bakers challenged to each make a dacquoise, made with three layers of fragile coiled meringue, sandwiched with coffee custard and topped with hazelnut praline, a dessert which also happens to be gluten free. For their final challenge, the bakers must push themselves out of their comfort zone to create showstopping novelty vegetable cakes - which must also be dairy free.

It is the semi-final and there are just four bakers left. This time it is the French round, and the challenges include savoury canapes and opera cake.

Each year thousands of people apply to The Great British Bake Off and only a handful are chosen, but what exactly is it like to take part? Talking candidly about their experience, the Class of 2012 return to the Bake Off tent to give a special insight to life inside the tent. They divulge how it felt to face the steely blue eyes and judgement of Mary and Paul, how they coped with having ingredients siphoned off by Mel and Sue, and to what extent practising bagels, pies, petit fours, meringues, hidden design cakes and gingerbread constructions took over their lives. Reliving their perfectly risen highs and soggy bottom lows, the bakers also reveal how their experience in a tent, in the middle of a field, in extreme weather conditions, has changed their lives.

It's the final of The Great British Bake Off! 13,000 applicants were narrowed down to 13 of Britain's best amateur bakers, and the 13 became three. There are just three final challenges standing between the bakers and the title of winner of the Great British Bake Off. Mary and Paul have chosen the final challenges to test the bakers on the areas in which they wanted to see how far they had grown in skill and creativity. The Signature Challenge asks them to create a technically difficult picnic pie - a savoury pie packed full of fillings that create a creative design, surrounded by shortcrust pastry with perfectly baked sides strong enough to be served out of the tin. The Technical is one of Paul's, as they are tasked to make 12 perfectly shaped pretzels, six savoury with rock salt and six sweet, flavoured with poppy seeds and topped with sweet orange zest and glaze. For the very final challenge in this year's Bake Off they must bake the ultimate showpiece in a baker's repertoire - a wedding cake. Three tiers that are their last chance to showcase their creative, baking brilliance. All of their efforts will be prepared for their family and friends at the GBBO summer garden party, who will be there to support the winner - but which of our female finalists will it be? Bake Off finalists; on your marks....get set......BAKE!

Mary and Paul take over the tent for the ultimate baking masterclass. Mary makes a whole orange cake and angel food cake, Paul makes breakfast muffins and olive bread sticks, and together they make a chocolate cake showstopper.

Paul and Mary show what they would have done in dessert and pie challenges. Mary: 'Tipsy Trifle', floating islands and 'Wobbly Apricot Tart'. Paul: custard tarts and spanakopita.

Paul and Mary show what they would have done in the biscuit and pastry test. Mary: ginger spiced traybake and tuiles with chocolate mousse. Paul :iced tea loaf, sweet dough brioche tete, and apricot couronne.

Paul and Mary show what they would have done for the challenges in the final weeks of the Bake Off. Paul: wheat-free crusty rye loaf and sweet and savory pretzels. Mary: sussex pond pudding, choux pastry religious, and an opera cake.