Re: US/UK dual citizenship - passport misery
I think that your friend should actually have surrendered his British passport to the nearest British Embassy/Consulate, once he had his US citizenship and then renounced his UK citizenship. I have no idea if such a procedure actually exists but I am sure he should have gone through the motions. As far as I know, an adult cannot have dual US citizenship.
I am sure that he is aware that he must now always file a US income tax return, no matter where in the world he is living nor for how long in the future he may do so. Failure to comply with this might result in the US IRS coming against him for tax evasion. As long as he is a US citizen he will have a responsibility to the aforementioned organization. It does not, unlike the UK Revenue, make deals. Furthermore, even were he to allow his US passport to lapse in the future and continue to travel (illegally in the eyes of Uncle Sam?) on a British passport, the US/IRS will still consider him a US citizen for the purposes of taxation and the requirement to adhere to US tax law! Do be warned.