Channel 4 today announces a new 2x60 series of Great Canal Journeys. National treasures Timothy West and Prunella Scales have been exploring canals for half a century – but now they embark on their most ambitious voyage ever – the waterways of India.

Tim takes the helm to explore the extraordinary Kerala backwaters: a one thousand mile network of palm-fringed lakes, rivers banked by rice paddies - and some very familiar-looking British-built canals. For millennia merchants from east and west have been drawn here to trade in ginger, cardamom and black pepper, making the backwaters a thriving trade route for spices.

All of life happens on Kerela’s back waters – Tim and Pru pass school bus-boats, laden cargo ships, and fishermen whose only tools are their hands. They explore a canal built by a local ruler to boost trade, make offerings at a temple raised up out of the waters, and, to Tim's delight, Pru dusts off her dancing shoes to learn the traditional Kerlan 'dance of the enchantress'.

They head on to what could be one of the most challenging voyage of Tim and Pru's lives... Leaving behind the safe confines of the canals, they head out into the unknown waters of the Brahmaputra river in the far north east of India. Unpredictable and wild, it's now rarely navigated, but in colonial times the river boasted a regular steam service carrying tea, bound for Britain.

Indian travel has been a family affair for Pru, whose father served in the Indian army, and whose grandfather shipped cloth in Bombay. Now Pru has the chance to see India through their eyes, as she follows in their footsteps along the old British trade route.

They are half a world away from home, but as long as they're together there are no limits to adventure for Tim and Pru.

Great Canal Journeys airs later this year.