1) Encrypt everything.
2) Do not use American products.
3) Develop as much tooling as you can in house.
4) Do not have direct connectivity to the outside world.
If your data stays out of the hands of GCHQ it wont be given to the NSA who will then sell it off to American enterprises UK is competing directly against.
In case you think that this is melodramatic see the ongoing lawsuit with trade secrets from Airbus, which mysteriously showed up in America.
Or Siemenn's nuclear centrifuge operating data, that mysteriously showed up in stuxnet.