Environment correspondent, BBC News
Fenland potato farmers could be badly affected by water shortages
We are standing under endless Fenland skies. It's not yet Eight O Clock, but already the sun is warm and high.
We are surveying three fields on Duncan Worth's farm. Before us, glossy green potato plants with their scented white flowers; to the left of us, maize to be used in power generation; to the right of us, wheat.
"It's been ideal growing weather recently," Duncan says, "sunshine and the right amount of rain."
But for how much longer? The hotter, drier summers predicted by climate change scientists could have a dramatic effect on this agricultural powerhouse of a region, and the thousands of jobs that it supports.
Where will the water come from to slake the thirst of these crops?
We're walking Duncan's fields with Dr Jerry Knox from Cranfield University, an adviser to, among others, the British Potato Council, and with Andy Brown from Anglian Water.
So will there be enough water to sustain the plants of the future in this rich, light soil?
"It's not so much a resource issue as a policy issue," says Dr Knox. "In other words, whether we want food with a low environmental footprint.
"We already import strawberries and lettuce from Southern Europe, where businesses are at risk from water shortages. We're exporting much of the problem.
"But farmers here do realise that some crops, like potatoes, may have to be grown in other parts of the UK in future."
"We're worried about water; we're not confident," says Mr Worth.
He and other farmers in the region are so concerned about the issue that they have started the Holbeach Marsh Water Transfer Project, looking at the feasibility of getting water from the River Welland to the marsh - making it accessible to agriculture.
But if projects like this proliferate in the future as water becomes more scarce, are we not robbing Peter to pay Paul?
"There's a fascinating triangle in the east of England between domestic use, agriculture and the environment," says Mr Brown.
"There are 750 sites of special scientific interest in our region, a large number of which are wetlands-based. We think we can get the balance right."
But as we finish our walk and head off for a cup of tea, all agree that it will take planning and perhaps some sacrifice to meet the many demands on the increasingly precious resource of water.