expat thinking of coming home

[expat]

True, but apparently there is an agreement between Spain and UK so that you don't pay tax twice on what's earned (once it's payed in Spain then Gordo wouldn't be able to claim any).

Not quite: the way it almost always works is this: you pay tax on your income in the place that you earned it. You are also due to pay tax on all your income, in the place that considers you resident; but with a credit against tax, equal to tax already paid elsewhere. At the very least, this means that you effectively pay tax at the rate of the higher of the 2 countries.

Among the Gotchas are: both places may consider you resident. They may both want to tax you on all income (you can not say to them, get your act together and then I'll pay)

Double taxation relief applies to income tax. Some of the money that you have to pay to the government may not be called "tax", in which case it will not be subject to double taxation relief. It may well be due in both places; or (for example like health care) may be done by taxation in one country and by compulsory health insurance in another: do not expect one country to let you off with taxes just because you have insurace in another. You may pay as you earn in one country, but in arrears in another. You may be regarded as "employed" by one country for tax purposes, but as "self-employed" by the other country - so each may declare that you are taxable there.

So, if some IR35 equivalent isn't in existence in Spain, then probably would make sense to based here methinks(?)

What do you think IR35 says? It seems to me that it says that you may be treated as if all or most of your turnover were income. That is already the case for contractors in most countries. Only in the UK do one-man-bands operate "companies" instead of being self-employed (but don't get me started....).

But the usual UK contractor's question, Am I In or Out of IR35, is not the question for a potential expat: it is simply, what is the income, and the cost of doing business, in this or that country?

[Antman]

golly thanks!

Definitely food for thought there