Adam Henson of BBC Countryfile was granted rare access to the biggest single glass house in the UK where a controversial crop is now being grown.

Here, on this East Anglia site, they used to grow food. But now the glasshouse has been converted to become one of the world’s largest producers of pharmaceutical-grade cannabis.

The producers are now able to grow and harvest three batches of this highly-specialised cannabis a year.

Adam sees the last plants of 2018 being harvested before being taken off site where the all-important CBD chemical is extracted...

Check out the broadcast here.