US Patent: Impact on Using Similar Variants in the UK

[Mech King]

If there is a patent that exists in the USA on a machine for example, is there any legal implication of using a similar variant of that machine in the UK?

If the patent only exists in the US, then what is stopping it being coppied and patented across europe? Surely this would prevent the patent in the USA from spreading across europe?

its a bit hypothetical, but i have been debating it with a colleague and we cannot agree. What are your thoughts?

 

[mgb_phys]

A patent stops you selling a machine in the country where the patent is registered.
You generally either register the patent in your major markets (US/EU) or take out a world wide (WIPO) patent, there are also a bunch of patent treaties where patents form one country automatically count in another.

It's a business desicsion, you can waste years and lot sof money patenting your advanced jet fighter design in a dozen little african countries - or just decide that they aren't likely to be a major market.

 

[Mech King]

Thanks for the clarification