Reply to post: "..Reaction Engines can keep most of their development work in the UK the better."

"..Reaction Engines can keep most of their development work in the UK the better."

Actually they do.

The test facility is in the US.

The HX was designed and built in the UK.

Which AFAIK is where the design and mfg operation is planning to stay.

BTW AFAIK this is the first new high temp,high speed airflow test site in the US for decades. I think they're hoping it will raise some fees testing out other peoples idea for hypersonic flight.