Might be a silly question - but do US border staff have to be US citizens? So would have to be flown out and work as an ex-pat and not recruited locally?
Immigration seems not a particularly skilled job, pretty much computer says either "yes" or "no" and the demand to "put your index finger here". For the US ones, the main skill seems to be an excellence in extreme arrogance and ability to talk down to every pax as if they are a criminal.
Why can't the US recruit local Brits to do this and train them in these "skills"?
1. Yes they MUST be US citizens however I think joint American/British citizens
are allowed to work for the CBP.
2. Yes they are US based and would have to be sent to the UK as expats which would mean somebody (BAA, CBP, etc) would have to pay their flights, housing, tax benefits, health insurance etc
3. If the US hired locals then the locals would let all their friends into the US without checking them.
Good Idea though! ^

I could make a fortune charging bribes to people who wanted to enter the US without the immigration procedures.