Thanks nun,
Assume I'm not taking FEIE, as I'm not yet sure if I'll be eligible.
So effectively you're saying that using tax credits, if I've only paid say £800 of tax in the UK, as only £4,000 of income was taxable. I will have to indicate only this amount on my US return?
That's quite steep. In dollars: that's $22,000 on my return, about £12,000 taxable after deductions, and then $1,200 in foreign tax credit. So I'd have to pay an additional $1,500 or so to the IRS on the money earned in the UK.
Would be great if they somehow honoured the personal allowance in the UK.