Michael Portillo's Great British Railway Journeys visits Hatfield, Stevenage, and the Lee Valley White Water Centre in Hertfordshire this week.

Wednesday, May 5's scheduled episode, Potters Bar to Cardington, sees Michael Portillo’s 1930s Bradshaw-inspired travels resume in leafy Hertfordshire, after journeying from Colchester in Essex to Chadwell Heath the previous day.

Welwyn Hatfield Times: Michael Portillo with Richard Hounslow and British slalom canoeist Bradley Forbes-Cryans at Lee Valley White Water Centre during the latest series of Great British Railway Journeys.Michael Portillo with Richard Hounslow and British slalom canoeist Bradley Forbes-Cryans at Lee Valley White Water Centre during the latest series of Great British Railway Journeys. (Image: BBC/Naked West/Fremantle)

Episode 8 of the latest series on BBC Two sees the intrepid former MP attempt a canoe slalom course at the Lee Valley White Water Centre in Waltham Cross, built for the 2012 London Olympics.

Former competitive canoeist Sue Hornby tells Michael how British canoeists first competed at the politically-charged Berlin Games in 1936.

Britain won a gold and a silver medal here at the London Olympics, and Michael’s hopes are high as he takes to the paddling lake.

Welwyn Hatfield Times: Michael Portillo at Lee Valley White Water Centre during series 12 of Great British Railway Journeys.Michael Portillo at Lee Valley White Water Centre during series 12 of Great British Railway Journeys. (Image: BBC/Naked West/Fremantle)

Known for his colourful shirts and jackets, train fan Michael then journeys to Hatfield and visits the country estate of author Dame Barbara Cartland.

The novelist’s eldest son welcomes Michael to Camfield Place with a gift for his onward journey, 'A Train to Love', one of the 723 books written by the queen of romance.

Welwyn Hatfield Times: Michael Portillo visits Allied Bakeries in Stevenage on his Great British Railway Journeys.Michael Portillo visits Allied Bakeries in Stevenage on his Great British Railway Journeys. (Image: BBC/Naked West/Fremantle)

In Stevenage, Michael learns how, in 1935, a new enterprise boosted production of the nation's daily loaf with a factory in the town.

Allied Bakeries now produces 1.8 million loaves a week, and Michael marvels at the scale of the operation while enjoying the smell of freshly baked bread.

Welwyn Hatfield Times: Michael Portillo at Allied Bakeries in Stevenage for Great British Railway Journeys on BBC Two.Michael Portillo at Allied Bakeries in Stevenage for Great British Railway Journeys on BBC Two. (Image: BBC/Naked West/Fremantle)

Crossing the county border into Bedfordshire, presenter Michael reaches Sandy, from which he heads for Cardington.

Here the level countryside is dominated by two breathtakingly vast sheds.

In Hangar No 2, Michael hears the shocking story of the 'Titanic of the skies', the R101 airship, which crashed on its first long-haul voyage.

Of the 54 passengers and crew on board, 48 were killed or later died from their injuries.

Welwyn Hatfield Times: Michael Portillo at the Cardington Airship Sheds in episode 8 of Great British Railway Journeys.Michael Portillo at the Cardington Airship Sheds in episode 8 of Great British Railway Journeys. (Image: BBC/Naked West/Fremantle)

Steered by his trusty Bradshaw’s guide, Michael Portillo travels from Sawbridgeworth in Herts to the university city of Cambridge in Thursday May 6's episode on BBC Two.

The Bushey-born broadcaster first heads for the Hertfordshire village of Perry Green, where, in 1940, a young couple fleeing the bombing of London chose to make their home.

Sculptor Henry Moore became one of the defining artists of British modernism, and his sculptures were set in wonderful landscaped grounds and gardens created by his wife, Irina.

Welwyn Hatfield Times: Michael Portillo in series 12 of Great British Railway Journeys.Michael Portillo in series 12 of Great British Railway Journeys. (Image: BBC/Naked West/Fremantle)

Michael explores the monumental Reclining Figure, and finds out about the artist’s life and work.

In Cambridge, Michael revisits his former university to hear about a treacherous time in its past.

In Trinity Lane, he learns how during the 1920s and 30s, students of Trinity College were recruited to spy for the Soviet Union.

The former Enfield Southgate MP also remembers his own reaction while he was working for Margaret Thatcher in 1979, when the fourth man was unmasked.

Welwyn Hatfield Times: Michael Portillo presents Great British Railway Journeys on BBC Two.Michael Portillo presents Great British Railway Journeys on BBC Two. (Image: BBC/Naked West/Fremantle)

Across the city, at the Cavendish Laboratory, Michael meets a man with a job like no other.

Lab director Andy Parker smashes particles with the world’s largest particle accelerator, the Large Hadron Collider, in Geneva.

He shows Michael the LHC’s forerunner, the accelerator with which John Cockroft and Ernest Walton made the first controlled splitting of the atom in 1932.

In Impington, to the north of Cambridge, Michael investigates the progressive architecture of the village school and finds it was built by the founder of the Bauhaus school, Walter Gropius, in the 1930s.

Welwyn Hatfield Times: Michael Portillo with Sir Mark Prescott at the National Horse Racing Museum, Newmarket, during episode 10 of Great British Railway Journeys series 12.Michael Portillo with Sir Mark Prescott at the National Horse Racing Museum, Newmarket, during episode 10 of Great British Railway Journeys series 12. (Image: BBC/Naked West/Fremantle)

Portillo's East Anglian adventures end on Friday, May 7 with the train traveller heading from Newmarket's famous racecourse to Walsingham in Norfolk.

Series 12 of Great British Railway Journeys can be seen on BBC Two, from Monday to Friday, at 6.30pm each night.

Welwyn Hatfield Times: Michael Portillo at Wells & Walsingham Light Railway, Norfolk, in episode 10 of Great British Railway Journeys.Michael Portillo at Wells & Walsingham Light Railway, Norfolk, in episode 10 of Great British Railway Journeys. (Image: BBC/Naked West/Fremantle)