[isatrader]

It looks like Interactive Brokers have added an ISA finally. So might be worth looking if you trade US stocks from the UK. 

https://www.interactivebrokers.co.uk/en/...hp?f=50549

FX Handling
IBUK will automatically convert currencies when trading non-GBP denominated securities. To do this, IBUK will engage in “spot” currency transactions on your behalf in order to settle your buy orders or convert the proceed of a sell order. IBUK will base the exchange rate off the spot exchange rate at the time of trade 0.03% fee.


Here's a referral link if you want to get an interactive brokers account: https://ibkr.com/referral/david274